diff --git a/LookInside.xcodeproj/project.pbxproj b/LookInside.xcodeproj/project.pbxproj
index 1a80531d..f6531b67 100644
--- a/LookInside.xcodeproj/project.pbxproj
+++ b/LookInside.xcodeproj/project.pbxproj
@@ -22,6 +22,7 @@
 		E972100D2FC2E5C0003AAEA6 /* InjectionServiceInterface in Frameworks */ = {isa = PBXBuildFile; productRef = E972100C2FC2E5C0003AAEA6 /* InjectionServiceInterface */; };
 		E9FE990C3026C657008692AF /* UIFoundation in Frameworks */ = {isa = PBXBuildFile; productRef = E9FE990B3026C657008692AF /* UIFoundation */; };
 		E9FE990E3026C657008692AF /* UIFoundationToolbox in Frameworks */ = {isa = PBXBuildFile; productRef = E9FE990D3026C657008692AF /* UIFoundationToolbox */; };
+		E9FE99103026C657008692AF /* UIFoundationSettingsUI in Frameworks */ = {isa = PBXBuildFile; productRef = E9FE990F3026C657008692AF /* UIFoundationSettingsUI */; };
 		F0F0A10E2FD0000100A1B2C3 /* FoundationToolbox in Frameworks */ = {isa = PBXBuildFile; productRef = F0F0A10D2FD0000100A1B2C3 /* FoundationToolbox */; };
 /* End PBXBuildFile section */
 
@@ -193,9 +194,6 @@
 				Measure/MeasureController.swift,
 				Measure/MeasureResultView.swift,
 				Other/VersionComparer.swift,
-				Preference/PreferenceView.swift,
-				Preference/PreferenceWindowController.swift,
-				PrivateDiscriminator/PrivateDiscriminatorSettingsWindowController.swift,
 				PrivateDiscriminator/PrivateDiscriminatorStore.swift,
 				Read/ArchiveCoding.swift,
 				Read/ArchiveDocument.swift,
@@ -204,6 +202,9 @@
 				Read/ReadScreenshotLookup.swift,
 				Read/ReadViewController.swift,
 				Read/ReadWindowController.swift,
+				Settings/GeneralSettingsPage.swift,
+				Settings/PrivateDiscriminatorSettingsPage.swift,
+				Settings/SettingsPages.swift,
 				Static/MessageManager.swift,
 				Static/Preview/DisplayItemNode.swift,
 				Static/Preview/PreviewController.swift,
@@ -299,6 +300,7 @@
 				E972100B2FC2E5C0003AAEA6 /* HelperCommunication in Frameworks */,
 				E972100D2FC2E5C0003AAEA6 /* InjectionServiceInterface in Frameworks */,
 				E9FE990E3026C657008692AF /* UIFoundationToolbox in Frameworks */,
+				E9FE99103026C657008692AF /* UIFoundationSettingsUI in Frameworks */,
 				F0F0A10E2FD0000100A1B2C3 /* FoundationToolbox in Frameworks */,
 				15FFB4D96CB7375162952FFE /* LookInsideActivation in Frameworks */,
 				79CC3F736CA547232F1827F4 /* LookInsideActivationUI in Frameworks */,
@@ -366,6 +368,7 @@
 				E972100C2FC2E5C0003AAEA6 /* InjectionServiceInterface */,
 				E9FE990B3026C657008692AF /* UIFoundation */,
 				E9FE990D3026C657008692AF /* UIFoundationToolbox */,
+				E9FE990F3026C657008692AF /* UIFoundationSettingsUI */,
 				F0F0A10D2FD0000100A1B2C3 /* FoundationToolbox */,
 				4CF60A9D44E04A6BE91035EF /* LookInsideActivation */,
 				F05DCA7C93CF923C02603F72 /* LookInsideActivationUI */,
@@ -884,6 +887,7 @@
 			};
 			traits = (
 				AppleInternal,
+				Settings,
 			);
 		};
 		F0F0A10A2FD0000100A1B2C3 /* XCRemoteSwiftPackageReference "FrameworkToolbox" */ = {
@@ -952,6 +956,11 @@
 			package = E9FE990A3026C657008692AF /* XCRemoteSwiftPackageReference "UIFoundation" */;
 			productName = UIFoundationToolbox;
 		};
+		E9FE990F3026C657008692AF /* UIFoundationSettingsUI */ = {
+			isa = XCSwiftPackageProductDependency;
+			package = E9FE990A3026C657008692AF /* XCRemoteSwiftPackageReference "UIFoundation" */;
+			productName = UIFoundationSettingsUI;
+		};
 		F05DCA7C93CF923C02603F72 /* LookInsideActivationUI */ = {
 			isa = XCSwiftPackageProductDependency;
 			package = E81BCA16A46AEA38803B27B7 /* XCLocalSwiftPackageReference "Packages/LookInsideActivation" */;
diff --git a/LookInside/DebugE2E/DebugUISnapshots.swift b/LookInside/DebugE2E/DebugUISnapshots.swift
index 244933b9..bf206868 100644
--- a/LookInside/DebugE2E/DebugUISnapshots.swift
+++ b/LookInside/DebugE2E/DebugUISnapshots.swift
@@ -217,10 +217,10 @@
             try await readRoundTrip(exported)
 
             // Windows of their own.
-            NavigationManager.shared.showPreference()
-            try await captureStandaloneWindow("preferences", controllerKey: "preferenceWindowController")
+            NavigationManager.shared.showSettings()
+            try await captureStandaloneWindow("settings") { NavigationManager.shared.settingsWindowController }
             NavigationManager.shared.showAbout()
-            try await captureStandaloneWindow("about", controllerKey: "aboutWindowController")
+            try await captureStandaloneWindow("about") { NavigationManager.shared.aboutWindowController }
             try await captureActivationWindow()
         }
 
@@ -276,10 +276,9 @@
             window.close()
         }
 
-        private func captureStandaloneWindow(_ name: String, controllerKey: String) async throws {
-            let navigation = NavigationManager.shared
+        private func captureStandaloneWindow(_ name: String, controller: () -> NSWindowController?) async throws {
             let window = try await waitFor("the \(name) window") {
-                (navigation.value(forKey: controllerKey) as? NSWindowController)?.window.flatMap { $0.isVisible ? $0 : nil }
+                controller()?.window.flatMap { $0.isVisible ? $0 : nil }
             }
             quietWindows()
             window.center()
diff --git a/LookInside/Localizable.xcstrings b/LookInside/Localizable.xcstrings
index d0640747..b8822b5f 100644
--- a/LookInside/Localizable.xcstrings
+++ b/LookInside/Localizable.xcstrings
@@ -1,9 +1,6 @@
 {
   "sourceLanguage" : "en",
   "strings" : {
-    "" : {
-
-    },
     " / " : {
       "comment" : "Separator between imported/autosaved CSV sources",
       "extractionState" : "stale",
@@ -8342,6 +8339,89 @@
         }
       }
     },
+    "Dark" : {
+      "comment" : "Caption under the dark appearance thumbnail in the Settings window.",
+      "localizations" : {
+        "ar" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "داكن"
+          }
+        },
+        "de" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Dunkel"
+          }
+        },
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Dark"
+          }
+        },
+        "es" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Oscuro"
+          }
+        },
+        "fr" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Sombre"
+          }
+        },
+        "it" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Scuro"
+          }
+        },
+        "ja" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "ダーク"
+          }
+        },
+        "ko" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "다크"
+          }
+        },
+        "pt-BR" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Escuro"
+          }
+        },
+        "ru" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Тёмный"
+          }
+        },
+        "vi" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Tối"
+          }
+        },
+        "zh-Hans" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "深色"
+          }
+        },
+        "zh-Hant" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "深色"
+          }
+        }
+      }
+    },
     "Dark Mode" : {
       "localizations" : {
         "ar" : {
@@ -9241,6 +9321,7 @@
       }
     },
     "Done" : {
+      "extractionState" : "stale",
       "localizations" : {
         "ar" : {
           "stringUnit" : {
@@ -13927,6 +14008,89 @@
         }
       }
     },
+    "General" : {
+      "comment" : "Title of the Settings window's General page.",
+      "localizations" : {
+        "ar" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "عام"
+          }
+        },
+        "de" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Allgemein"
+          }
+        },
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "General"
+          }
+        },
+        "es" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "General"
+          }
+        },
+        "fr" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Général"
+          }
+        },
+        "it" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Generali"
+          }
+        },
+        "ja" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "一般"
+          }
+        },
+        "ko" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "일반"
+          }
+        },
+        "pt-BR" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Geral"
+          }
+        },
+        "ru" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Основные"
+          }
+        },
+        "vi" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Cài đặt chung"
+          }
+        },
+        "zh-Hans" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "通用"
+          }
+        },
+        "zh-Hant" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "一般"
+          }
+        }
+      }
+    },
     "Geometry" : {
       "comment" : "Native region detail field title",
       "localizations" : {
@@ -15002,6 +15166,89 @@
         }
       }
     },
+    "Hierarchy" : {
+      "comment" : "Header of the Settings window's group of hierarchy settings.",
+      "localizations" : {
+        "ar" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "التسلسل الهرمي"
+          }
+        },
+        "de" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Hierarchie"
+          }
+        },
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Hierarchy"
+          }
+        },
+        "es" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Jerarquía"
+          }
+        },
+        "fr" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Hiérarchie"
+          }
+        },
+        "it" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Gerarchia"
+          }
+        },
+        "ja" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "階層"
+          }
+        },
+        "ko" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "계층 구조"
+          }
+        },
+        "pt-BR" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Hierarquia"
+          }
+        },
+        "ru" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Иерархия"
+          }
+        },
+        "vi" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Phân cấp"
+          }
+        },
+        "zh-Hans" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "层级"
+          }
+        },
+        "zh-Hant" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "階層"
+          }
+        }
+      }
+    },
     "Hierarchy Depth" : {
       "comment" : "View menu submenu",
       "localizations" : {
@@ -19858,6 +20105,89 @@
         }
       }
     },
+    "Light" : {
+      "comment" : "Caption under the light appearance thumbnail in the Settings window.",
+      "localizations" : {
+        "ar" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "فاتح"
+          }
+        },
+        "de" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Hell"
+          }
+        },
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Light"
+          }
+        },
+        "es" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Claro"
+          }
+        },
+        "fr" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Clair"
+          }
+        },
+        "it" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Chiaro"
+          }
+        },
+        "ja" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "ライト"
+          }
+        },
+        "ko" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "라이트"
+          }
+        },
+        "pt-BR" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Claro"
+          }
+        },
+        "ru" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Светлый"
+          }
+        },
+        "vi" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Sáng"
+          }
+        },
+        "zh-Hans" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "浅色"
+          }
+        },
+        "zh-Hant" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "淺色"
+          }
+        }
+      }
+    },
     "Light Mode" : {
       "localizations" : {
         "ar" : {
@@ -22327,6 +22657,89 @@
         }
       }
     },
+    "Modules" : {
+      "comment" : "Header of the Private Discriminator settings group that lists the imported modules.",
+      "localizations" : {
+        "ar" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "الوحدات"
+          }
+        },
+        "de" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Module"
+          }
+        },
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Modules"
+          }
+        },
+        "es" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Módulos"
+          }
+        },
+        "fr" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Modules"
+          }
+        },
+        "it" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Moduli"
+          }
+        },
+        "ja" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "モジュール"
+          }
+        },
+        "ko" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "모듈"
+          }
+        },
+        "pt-BR" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Módulos"
+          }
+        },
+        "ru" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Модули"
+          }
+        },
+        "vi" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Mô-đun"
+          }
+        },
+        "zh-Hans" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "模块"
+          }
+        },
+        "zh-Hant" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "模組"
+          }
+        }
+      }
+    },
     "More than one connected device has a LookInside Injector ready." : {
       "comment" : "Alert body in device chooser",
       "localizations" : {
@@ -27278,6 +27691,7 @@
       }
     },
     "Preferences" : {
+      "extractionState" : "stale",
       "localizations" : {
         "ar" : {
           "stringUnit" : {
@@ -27361,6 +27775,7 @@
     },
     "Preferences…" : {
       "comment" : "App menu item",
+      "extractionState" : "stale",
       "localizations" : {
         "ar" : {
           "stringUnit" : {
@@ -27690,6 +28105,7 @@
       }
     },
     "Private Discriminator" : {
+      "comment" : "Title of the Settings window's Private Discriminator page.",
       "localizations" : {
         "ar" : {
           "stringUnit" : {
@@ -27772,6 +28188,7 @@
       }
     },
     "Private Discriminator Settings" : {
+      "extractionState" : "stale",
       "localizations" : {
         "ar" : {
           "stringUnit" : {
@@ -27855,6 +28272,7 @@
     },
     "Private Discriminator Settings…" : {
       "comment" : "App menu item",
+      "extractionState" : "stale",
       "localizations" : {
         "ar" : {
           "stringUnit" : {
@@ -30079,6 +30497,172 @@
         }
       }
     },
+    "Reset Settings" : {
+      "comment" : "Title of the row on the Settings window's General page whose button resets the page's settings.",
+      "localizations" : {
+        "ar" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "إعادة تعيين الإعدادات"
+          }
+        },
+        "de" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Einstellungen zurücksetzen"
+          }
+        },
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Reset Settings"
+          }
+        },
+        "es" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Restablecer ajustes"
+          }
+        },
+        "fr" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Réinitialiser les réglages"
+          }
+        },
+        "it" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Ripristina impostazioni"
+          }
+        },
+        "ja" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "設定をリセット"
+          }
+        },
+        "ko" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "설정 재설정"
+          }
+        },
+        "pt-BR" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Redefinir Ajustes"
+          }
+        },
+        "ru" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Сбросить настройки"
+          }
+        },
+        "vi" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Đặt lại cài đặt"
+          }
+        },
+        "zh-Hans" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "重置设置"
+          }
+        },
+        "zh-Hant" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "重置設定"
+          }
+        }
+      }
+    },
+    "Resets the settings on this page to their default values." : {
+      "comment" : "Description under Reset Settings on the Settings window's General page.",
+      "localizations" : {
+        "ar" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "يعيد تعيين الإعدادات في هذه الصفحة إلى قيمها الافتراضية."
+          }
+        },
+        "de" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Setzt die Einstellungen auf dieser Seite auf ihre Standardwerte zurück."
+          }
+        },
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Resets the settings on this page to their default values."
+          }
+        },
+        "es" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Restablece los ajustes de esta página a sus valores predeterminados."
+          }
+        },
+        "fr" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Réinitialise les réglages de cette page à leurs valeurs par défaut."
+          }
+        },
+        "it" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Ripristina le impostazioni di questa pagina ai valori predefiniti."
+          }
+        },
+        "ja" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "このページの設定をデフォルト値にリセットします。"
+          }
+        },
+        "ko" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "이 페이지의 설정을 기본값으로 재설정합니다."
+          }
+        },
+        "pt-BR" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Redefine os ajustes desta página para os valores padrão."
+          }
+        },
+        "ru" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Сбрасывает настройки на этой странице к значениям по умолчанию."
+          }
+        },
+        "vi" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Đặt lại các cài đặt trên trang này về giá trị mặc định."
+          }
+        },
+        "zh-Hans" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "将本页的设置重置为默认值。"
+          }
+        },
+        "zh-Hant" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "將本頁的設定重置為預設值。"
+          }
+        }
+      }
+    },
     "Resolve Swift private-discriminator hashes from imported module CSVs. Disabled by default." : {
       "localizations" : {
         "ar" : {
@@ -32059,6 +32643,172 @@
         }
       }
     },
+    "Settings" : {
+      "comment" : "Title of the Settings window.",
+      "localizations" : {
+        "ar" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "الإعدادات"
+          }
+        },
+        "de" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Einstellungen"
+          }
+        },
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Settings"
+          }
+        },
+        "es" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Ajustes"
+          }
+        },
+        "fr" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Réglages"
+          }
+        },
+        "it" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Impostazioni"
+          }
+        },
+        "ja" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "設定"
+          }
+        },
+        "ko" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "설정"
+          }
+        },
+        "pt-BR" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Ajustes"
+          }
+        },
+        "ru" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Настройки"
+          }
+        },
+        "vi" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Cài đặt"
+          }
+        },
+        "zh-Hans" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "设置"
+          }
+        },
+        "zh-Hant" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "設定"
+          }
+        }
+      }
+    },
+    "Settings…" : {
+      "comment" : "App menu item",
+      "localizations" : {
+        "ar" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "الإعدادات…"
+          }
+        },
+        "de" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Einstellungen …"
+          }
+        },
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Settings…"
+          }
+        },
+        "es" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Ajustes…"
+          }
+        },
+        "fr" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Réglages…"
+          }
+        },
+        "it" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Impostazioni…"
+          }
+        },
+        "ja" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "設定…"
+          }
+        },
+        "ko" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "설정…"
+          }
+        },
+        "pt-BR" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Ajustes…"
+          }
+        },
+        "ru" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Настройки…"
+          }
+        },
+        "vi" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Cài đặt…"
+          }
+        },
+        "zh-Hans" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "设置…"
+          }
+        },
+        "zh-Hant" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "設定…"
+          }
+        }
+      }
+    },
     "Shape parameters or path are unavailable. The overlay shows dashed layout bounds without a hit-area fill." : {
       "comment" : "Node detail note",
       "localizations" : {
@@ -35106,6 +35856,89 @@
         }
       }
     },
+    "System" : {
+      "comment" : "Caption under the appearance thumbnail that follows the system's light or dark setting, in the Settings window.",
+      "localizations" : {
+        "ar" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "النظام"
+          }
+        },
+        "de" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "System"
+          }
+        },
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "System"
+          }
+        },
+        "es" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Sistema"
+          }
+        },
+        "fr" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Système"
+          }
+        },
+        "it" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Sistema"
+          }
+        },
+        "ja" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "システム"
+          }
+        },
+        "ko" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "시스템"
+          }
+        },
+        "pt-BR" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Sistema"
+          }
+        },
+        "ru" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Система"
+          }
+        },
+        "vi" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Hệ thống"
+          }
+        },
+        "zh-Hans" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "系统"
+          }
+        },
+        "zh-Hant" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "系統"
+          }
+        }
+      }
+    },
     "System Default" : {
       "localizations" : {
         "ar" : {
@@ -39530,6 +40363,89 @@
         }
       }
     },
+    "Timeouts" : {
+      "comment" : "Header of the Settings window's group of request timeouts.",
+      "localizations" : {
+        "ar" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "المهلات"
+          }
+        },
+        "de" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Zeitlimits"
+          }
+        },
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Timeouts"
+          }
+        },
+        "es" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Tiempos de espera"
+          }
+        },
+        "fr" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Délais d’attente"
+          }
+        },
+        "it" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Timeout"
+          }
+        },
+        "ja" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "タイムアウト"
+          }
+        },
+        "ko" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "제한 시간"
+          }
+        },
+        "pt-BR" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Tempos Limite"
+          }
+        },
+        "ru" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Тайм-ауты"
+          }
+        },
+        "vi" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Thời gian chờ"
+          }
+        },
+        "zh-Hans" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "超时"
+          }
+        },
+        "zh-Hant" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "逾時"
+          }
+        }
+      }
+    },
     "to measure between it and selected %@." : {
       "localizations" : {
         "ar" : {
diff --git a/LookInside/Manager/AppMenuManager.swift b/LookInside/Manager/AppMenuManager.swift
index 9b49439a..c0a96a0b 100644
--- a/LookInside/Manager/AppMenuManager.swift
+++ b/LookInside/Manager/AppMenuManager.swift
@@ -43,7 +43,7 @@ final class AppMenuManager: NSObject, NSMenuDelegate {
 
     private enum Tag {
         static let about = 11
-        static let preferences = 12
+        static let settings = 12
         static let checkUpdates = 13
         static let activateSwiftUISupport = 14
         static let swiftUISupportLicense = 15
@@ -51,7 +51,6 @@ final class AppMenuManager: NSObject, NSMenuDelegate {
         static let purchaseSwiftUISupport = 17
         static let swiftUISupportCustomerSupport = 18
         static let swiftUISupportSubmenu = 19
-        static let privateDiscriminatorSettings = 20
 
         static let reload = 21
         static let dimension = 22
@@ -152,8 +151,7 @@ final class AppMenuManager: NSObject, NSMenuDelegate {
         menu.delegate = self
         menu.addItem(item(String(format: NSLocalizedString("About %@", comment: ""), appName), action: #selector(handleAbout), tag: Tag.about))
         menu.addItem(.separator())
-        menu.addItem(item(NSLocalizedString("Preferences…", comment: ""), action: #selector(handlePreferences), key: ",", modifiers: .command, tag: Tag.preferences))
-        menu.addItem(item(NSLocalizedString("Private Discriminator Settings…", comment: ""), action: #selector(handlePrivateDiscriminatorSettings), tag: Tag.privateDiscriminatorSettings))
+        menu.addItem(item(NSLocalizedString("Settings…", comment: ""), action: #selector(handleSettings), key: ",", modifiers: .command, tag: Tag.settings))
         menu.addItem(.separator())
         menu.addItem(item(NSLocalizedString("Check for Updates…", comment: ""), action: #selector(handleCheckUpdates), tag: Tag.checkUpdates))
         menu.addItem(.separator())
@@ -432,12 +430,8 @@ final class AppMenuManager: NSObject, NSMenuDelegate {
         NavigationManager.shared.showAbout()
     }
 
-    @objc private func handlePreferences() {
-        NavigationManager.shared.showPreference()
-    }
-
-    @objc private func handlePrivateDiscriminatorSettings() {
-        PrivateDiscriminatorSettingsWindowController.showSettingsWindow()
+    @objc private func handleSettings() {
+        NavigationManager.shared.showSettings()
     }
 
     @objc private func handleCheckUpdates() {
diff --git a/LookInside/Manager/NavigationManager.swift b/LookInside/Manager/NavigationManager.swift
index 01c1da71..4a02e253 100644
--- a/LookInside/Manager/NavigationManager.swift
+++ b/LookInside/Manager/NavigationManager.swift
@@ -5,11 +5,12 @@
 //  Created by Li Kai on 2018/11/3.
 //  https://lookin.work
 //
-//  Opens the app's standalone windows: launch, preferences, about, the JSON
+//  Opens the app's standalone windows: launch, settings, about, the JSON
 //  viewer, and readers for `.lookin` files or in-memory hierarchies.
 //
 
 import AppKit
+import UIFoundationSettingsUI
 
 @MainActor
 final class NavigationManager: NSObject, NSWindowDelegate {
@@ -21,9 +22,22 @@ final class NavigationManager: NSObject, NSWindowDelegate {
 
     @objc private(set) var launchWindowController: LaunchWindowController?
 
-    // Read by name (KVC) by the DEBUG UI snapshots.
-    @objc private(set) var preferenceWindowController: PreferenceWindowController?
-    @objc private(set) var aboutWindowController: AboutWindowController?
+    /// Kept for the app's lifetime rather than dropped on close, so the
+    /// window opens again on the page the user left it on.
+    private(set) lazy var settingsWindowController = SettingsWindowController(
+        configuration: SettingsConfiguration(
+            title: String(localized: "Settings", comment: "Title of the Settings window."),
+            // The sidebar is 20 points wider than UIFoundation's default so
+            // "Private Discriminator" fits; the window grows by as much, so
+            // the pages keep the default width.
+            contentWidth: 735,
+            sidebarWidth: 205,
+            sidebarIconSize: 15
+        ),
+        pages: { SettingsPages.make() }
+    )
+
+    private(set) var aboutWindowController: AboutWindowController?
     private var jsonWindowController: JSONAttributeWindowController?
 
     /// Set by the hierarchy view from its top inset.
@@ -45,14 +59,8 @@ final class NavigationManager: NSObject, NSWindowDelegate {
         launchWindowController = nil
     }
 
-    @objc func showPreference() {
-        let controller = preferenceWindowController ?? {
-            let controller = PreferenceWindowController()
-            controller.window?.delegate = self
-            return controller
-        }()
-        preferenceWindowController = controller
-        controller.showWindow(self)
+    @objc func showSettings() {
+        settingsWindowController.showWindow(self)
     }
 
     @objc func showAbout() {
@@ -116,9 +124,7 @@ final class NavigationManager: NSObject, NSWindowDelegate {
 
     func windowWillClose(_ notification: Notification) {
         let closingWindow = notification.object as? NSWindow
-        if closingWindow == preferenceWindowController?.window {
-            preferenceWindowController = nil
-        } else if closingWindow == aboutWindowController?.window {
+        if closingWindow == aboutWindowController?.window {
             aboutWindowController = nil
         }
         // Live and archive document windows belong to NSDocumentController,
diff --git a/LookInside/Preference/PreferenceView.swift b/LookInside/Preference/PreferenceView.swift
deleted file mode 100644
index 5daf5d61..00000000
--- a/LookInside/Preference/PreferenceView.swift
+++ /dev/null
@@ -1,389 +0,0 @@
-import AppKit
-import SwiftUI
-
-public final class PreferenceHostingController: NSViewController {
-    override public func loadView() {
-        view = NSHostingView(rootView: PreferenceRootView())
-    }
-}
-
-private struct PreferenceRootView: View {
-    @StateObject private var model = PreferenceViewModel()
-
-    var body: some View {
-        VStack(spacing: 0) {
-            ScrollView {
-                VStack(alignment: .leading, spacing: 0) {
-                    Text("Preferences")
-                        .font(.system(size: 24, weight: .semibold))
-                        .padding(.bottom, 18)
-
-                    PreferenceRow(
-                        title: "Appearance",
-                        message: nil,
-                        controlWidth: 300
-                    ) {
-                        Picker("Appearance", selection: model.appearanceTypeBinding) {
-                            Text("Dark Mode").tag(0)
-                            Text("Light Mode").tag(1)
-                            Text("System Default").tag(2)
-                        }
-                        .pickerStyle(.segmented)
-                    }
-
-                    PreferenceDivider()
-
-                    PreferenceRow(
-                        title: "Color Format",
-                        message: model.colorFormatMessage,
-                        controlWidth: 220
-                    ) {
-                        Picker("Color Format", selection: model.colorFormatBinding) {
-                            Text(verbatim: "RGBA").tag(0)
-                            Text(verbatim: "HEX").tag(1)
-                        }
-                        .pickerStyle(.segmented)
-                    }
-
-                    PreferenceDivider()
-
-                    PreferenceRow(
-                        title: "Image contrast",
-                        message: "Adjust this option to use a deeper layer selection color.",
-                        controlWidth: 300
-                    ) {
-                        Picker("Image contrast", selection: model.imageContrastBinding) {
-                            Text("Normal").tag(0)
-                            Text("Medium").tag(1)
-                            Text("High").tag(2)
-                        }
-                        .pickerStyle(.segmented)
-                    }
-
-                    PreferenceDivider()
-
-                    PreferenceRow(
-                        title: "Double click",
-                        message: nil,
-                        controlWidth: 300
-                    ) {
-                        Picker("Double click", selection: model.doubleClickBinding) {
-                            Text("Expand or collapse layer").tag(0)
-                            Text("Focus on layer").tag(1)
-                        }
-                        .pickerStyle(.segmented)
-                    }
-
-                    PreferenceDivider()
-
-                    PreferenceRow(
-                        title: "Remember expansion state per app",
-                        message: "When on, the hierarchy expand/collapse state is restored per target-app bundle id across host and target-app restarts. The 20 most recently inspected apps are kept; toggling off preserves existing data but stops reading or writing it.",
-                        controlWidth: 80
-                    ) {
-                        Toggle("Remember expansion state per app", isOn: model.rememberExpansionStateBinding)
-                            .toggleStyle(.switch)
-                    }
-
-                    PreferenceDivider()
-
-                    PreferenceRow(
-                        title: "Hierarchy Timeout",
-                        message: "Timeout for hierarchy and hierarchy-details requests, in seconds. Default: 15s.",
-                        controlWidth: 168
-                    ) {
-                        TimeoutEditor(value: model.hierarchyTimeoutBinding)
-                    }
-
-                    #if DEBUG
-                        PreferenceDivider()
-
-                        PreferenceRow(
-                            title: "License Timeout",
-                            message: "Timeout for license challenge and verification requests, in seconds. Default: 5s.",
-                            controlWidth: 168
-                        ) {
-                            TimeoutEditor(value: model.licenseTimeoutBinding)
-                        }
-                    #endif
-                }
-                .padding(.horizontal, 32)
-                .padding(.top, 28)
-                .padding(.bottom, 24)
-            }
-
-            Divider()
-
-            HStack {
-                Spacer()
-                Button("Reset", role: .destructive) {
-                    model.reset()
-                }
-                .keyboardShortcut(.delete, modifiers: [.command, .shift])
-            }
-            .padding(.horizontal, 24)
-            .padding(.vertical, 14)
-            .background(.bar)
-        }
-        .frame(minWidth: 640, idealWidth: 660, minHeight: minimumHeight)
-        .background(Color(nsColor: .windowBackgroundColor))
-        .onAppear {
-            model.reload()
-        }
-    }
-
-    private var minimumHeight: CGFloat {
-        #if DEBUG
-            520
-        #else
-            455
-        #endif
-    }
-}
-
-private struct PreferenceRow<Control: View>: View {
-    let title: LocalizedStringKey
-    let message: LocalizedStringKey?
-    let controlWidth: CGFloat
-    @ViewBuilder let control: Control
-
-    var body: some View {
-        HStack(alignment: .firstTextBaseline, spacing: 24) {
-            VStack(alignment: .leading, spacing: 5) {
-                Text(title)
-                    .font(.system(size: 13, weight: .medium))
-                    .foregroundStyle(.primary)
-
-                if let message {
-                    Text(message)
-                        .font(.system(size: 12))
-                        .foregroundStyle(.secondary)
-                        .fixedSize(horizontal: false, vertical: true)
-                }
-            }
-            .frame(maxWidth: .infinity, alignment: .leading)
-
-            control
-                .labelsHidden()
-                .frame(width: controlWidth, alignment: .trailing)
-        }
-        .padding(.vertical, 13)
-    }
-}
-
-private struct PreferenceDivider: View {
-    var body: some View {
-        Divider()
-            .padding(.leading, 0)
-    }
-}
-
-private struct TimeoutEditor: View {
-    @Binding var value: Double
-
-    var body: some View {
-        HStack(spacing: 8) {
-            TextField(Self.emptyTitle, value: $value, formatter: Self.formatter)
-                .multilineTextAlignment(.trailing)
-                .textFieldStyle(.roundedBorder)
-                .frame(width: 72)
-
-            Text(verbatim: "s")
-                .foregroundStyle(.secondary)
-                .frame(width: 12, alignment: .leading)
-
-            Stepper("", value: $value, in: 0.1 ... 120, step: 1)
-                .labelsHidden()
-        }
-    }
-
-    private static let emptyTitle = ""
-
-    private static let formatter: NumberFormatter = {
-        let formatter = NumberFormatter()
-        formatter.minimum = 0.1
-        formatter.maximum = 120
-        formatter.minimumFractionDigits = 0
-        formatter.maximumFractionDigits = 2
-        formatter.allowsFloats = true
-        return formatter
-    }()
-}
-
-/// Stays an ObservableObject: as an @Observable model the segmented pickers
-/// laid out narrower than before (the ui-snapshots preferences scene).
-@MainActor
-private final class PreferenceViewModel: ObservableObject {
-    @Published private var appearanceType: Int
-    @Published private var colorFormat: Int
-    @Published private var imageContrast: Int
-    @Published private var doubleClickBehavior: Int
-    @Published private var rememberExpansionState: Bool
-    @Published private var hierarchyTimeout: Double
-
-    #if DEBUG
-        @Published private var licenseTimeout: Double
-    #endif
-
-    private let manager: PreferenceManager
-
-    init(manager: PreferenceManager = PreferenceManager.shared) {
-        self.manager = manager
-        appearanceType = manager.appearanceType.rawValue
-        colorFormat = manager.rgbaFormat ? 0 : 1
-        imageContrast = manager.imageContrastLevel
-        doubleClickBehavior = manager.doubleClickBehavior.rawValue
-        rememberExpansionState = manager.rememberExpansionState
-        hierarchyTimeout = manager.hierarchyRequestTimeoutInterval
-        #if DEBUG
-            licenseTimeout = manager.licenseHandshakeTimeoutInterval
-        #endif
-    }
-
-    var appearanceTypeBinding: Binding<Int> {
-        Binding(
-            get: { self.appearanceType },
-            set: { self.setAppearanceType($0) }
-        )
-    }
-
-    var colorFormatBinding: Binding<Int> {
-        Binding(
-            get: { self.colorFormat },
-            set: { self.setColorFormat($0) }
-        )
-    }
-
-    var imageContrastBinding: Binding<Int> {
-        Binding(
-            get: { self.imageContrast },
-            set: { self.setImageContrast($0) }
-        )
-    }
-
-    var doubleClickBinding: Binding<Int> {
-        Binding(
-            get: { self.doubleClickBehavior },
-            set: { self.setDoubleClickBehavior($0) }
-        )
-    }
-
-    var rememberExpansionStateBinding: Binding<Bool> {
-        Binding(
-            get: { self.rememberExpansionState },
-            set: { self.setRememberExpansionState($0) }
-        )
-    }
-
-    var hierarchyTimeoutBinding: Binding<Double> {
-        Binding(
-            get: { self.hierarchyTimeout },
-            set: { self.setHierarchyTimeout($0) }
-        )
-    }
-
-    #if DEBUG
-        var licenseTimeoutBinding: Binding<Double> {
-            Binding(
-                get: { self.licenseTimeout },
-                set: { self.setLicenseTimeout($0) }
-            )
-        }
-    #endif
-
-    var colorFormatMessage: LocalizedStringKey {
-        if colorFormat == 0 {
-            return "Color will be displayed in format like (255, 12, 34, 0.5). Alpha value is between 0 and 1."
-        }
-        return "Color will be displayed in format like #7e7e7eff. The components are #RRGGBBAA."
-    }
-
-    func reload() {
-        appearanceType = manager.appearanceType.rawValue
-        colorFormat = manager.rgbaFormat ? 0 : 1
-        imageContrast = manager.imageContrastLevel
-        doubleClickBehavior = manager.doubleClickBehavior.rawValue
-        rememberExpansionState = manager.rememberExpansionState
-        hierarchyTimeout = manager.hierarchyRequestTimeoutInterval
-        #if DEBUG
-            licenseTimeout = manager.licenseHandshakeTimeoutInterval
-        #endif
-    }
-
-    func reset() {
-        setAppearanceType(PreferredAppearanceType.system.rawValue)
-        setColorFormat(0)
-        setImageContrast(0)
-        setDoubleClickBehavior(DoubleClickBehavior.collapse.rawValue)
-        setRememberExpansionState(true)
-        setHierarchyTimeout(defaultHierarchyRequestTimeoutInterval)
-        setLicenseTimeoutIfAvailable(defaultLicenseHandshakeTimeoutInterval)
-
-        #if DEBUG
-            MessageManager.sharedInstance().reset()
-            manager.reset()
-            UserDefaults.standard.removeObject(forKey: "IgnoreFastModeTips")
-        #endif
-    }
-
-    private func setAppearanceType(_ rawValue: Int) {
-        guard let type = PreferredAppearanceType(rawValue: rawValue) else {
-            return
-        }
-        appearanceType = rawValue
-        manager.appearanceType = type
-    }
-
-    private func setColorFormat(_ rawValue: Int) {
-        colorFormat = rawValue
-        manager.rgbaFormat = rawValue == 0
-    }
-
-    private func setImageContrast(_ rawValue: Int) {
-        let clampedValue = min(max(rawValue, 0), 2)
-        imageContrast = clampedValue
-        manager.imageContrastLevel = clampedValue
-    }
-
-    private func setDoubleClickBehavior(_ rawValue: Int) {
-        guard let behavior = DoubleClickBehavior(rawValue: rawValue) else {
-            return
-        }
-        doubleClickBehavior = rawValue
-        manager.doubleClickBehavior = behavior
-    }
-
-    private func setRememberExpansionState(_ newValue: Bool) {
-        rememberExpansionState = newValue
-        manager.rememberExpansionState = newValue
-    }
-
-    private func setHierarchyTimeout(_ value: Double) {
-        let sanitizedValue = sanitizedTimeout(value, defaultValue: defaultHierarchyRequestTimeoutInterval)
-        hierarchyTimeout = sanitizedValue
-        manager.hierarchyRequestTimeoutInterval = sanitizedValue
-    }
-
-    private func setLicenseTimeoutIfAvailable(_ value: Double) {
-        #if DEBUG
-            setLicenseTimeout(value)
-        #else
-            _ = value
-        #endif
-    }
-
-    #if DEBUG
-        private func setLicenseTimeout(_ value: Double) {
-            let sanitizedValue = sanitizedTimeout(value, defaultValue: defaultLicenseHandshakeTimeoutInterval)
-            licenseTimeout = sanitizedValue
-            manager.licenseHandshakeTimeoutInterval = sanitizedValue
-        }
-    #endif
-
-    private func sanitizedTimeout(_ value: Double, defaultValue: Double) -> Double {
-        guard value.isFinite, value > 0 else {
-            return defaultValue
-        }
-        return min(max(value, 0.1), 120)
-    }
-}
diff --git a/LookInside/Preference/PreferenceWindowController.swift b/LookInside/Preference/PreferenceWindowController.swift
deleted file mode 100644
index cd33ca53..00000000
--- a/LookInside/Preference/PreferenceWindowController.swift
+++ /dev/null
@@ -1,62 +0,0 @@
-//
-//  PreferenceWindowController.swift
-//  LookInside
-//
-//  The Preferences window. Its content is the SwiftUI preference form
-//  (PreferenceView.swift) hosted inside an BaseViewController.
-//
-
-import AppKit
-
-final class PreferenceWindowController: WindowController {
-    @objc init() {
-        #if DEBUG
-            let windowHeight: CGFloat = 520
-        #else
-            let windowHeight: CGFloat = 455
-        #endif
-        let window = AppWindow(contentRect: NSRect(x: 0, y: 0, width: 660, height: windowHeight),
-                              styleMask: [.titled, .closable, .miniaturizable],
-                              backing: .buffered, defer: true)
-        window.isMovableByWindowBackground = true
-        window.title = NSLocalizedString("Preferences", comment: "")
-        window.titlebarAppearsTransparent = true
-        window.center()
-
-        super.init(window: window)
-        let viewController = PreferenceViewController()
-        window.contentView = viewController.view
-        contentViewController = viewController
-    }
-
-    @available(*, unavailable)
-    required init?(coder _: NSCoder) {
-        fatalError("init(coder:) is not supported")
-    }
-}
-
-final class PreferenceViewController: BaseViewController {
-    init() {
-        super.init(containerView: nil)
-        installPreferenceForm()
-    }
-
-    @available(*, unavailable)
-    required init?(coder _: NSCoder) {
-        fatalError("init(coder:) is not supported")
-    }
-
-    private func installPreferenceForm() {
-        let hostingController = PreferenceHostingController()
-        addChild(hostingController)
-        let hostedView = hostingController.view
-        hostedView.translatesAutoresizingMaskIntoConstraints = false
-        view.addSubview(hostedView)
-        NSLayoutConstraint.activate([
-            hostedView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
-            hostedView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
-            hostedView.topAnchor.constraint(equalTo: view.topAnchor),
-            hostedView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
-        ])
-    }
-}
diff --git a/LookInside/PrivateDiscriminator/PrivateDiscriminatorSettingsWindowController.swift b/LookInside/PrivateDiscriminator/PrivateDiscriminatorSettingsWindowController.swift
deleted file mode 100644
index 7de0cd97..00000000
--- a/LookInside/PrivateDiscriminator/PrivateDiscriminatorSettingsWindowController.swift
+++ /dev/null
@@ -1,392 +0,0 @@
-import AppKit
-import SwiftUI
-
-final class PrivateDiscriminatorSettingsWindowController: NSWindowController {
-    private static let sharedController = PrivateDiscriminatorSettingsWindowController()
-
-    @objc(showSettingsWindow)
-    static func showSettingsWindow() {
-        sharedController.showWindow(nil)
-        sharedController.window?.makeKeyAndOrderFront(nil)
-        NSApp.activate(ignoringOtherApps: true)
-    }
-
-    private init() {
-        let window = NSWindow(
-            contentRect: NSRect(x: 0, y: 0, width: 660, height: 640),
-            styleMask: [.titled, .closable, .miniaturizable, .resizable],
-            backing: .buffered,
-            defer: false
-        )
-        window.title = NSLocalizedString("Private Discriminator Settings", comment: "")
-        window.titlebarAppearsTransparent = true
-        window.isReleasedWhenClosed = false
-        window.minSize = NSSize(width: 640, height: 520)
-        window.contentViewController = NSHostingController(rootView: PrivateDiscriminatorSettingsRootView())
-        window.center()
-        super.init(window: window)
-    }
-
-    @available(*, unavailable)
-    required init?(coder _: NSCoder) {
-        fatalError("init(coder:) has not been implemented")
-    }
-}
-
-private struct PrivateDiscriminatorSettingsRootView: View {
-    private var store = PrivateDiscriminatorStore.shared
-    @State private var importError: String?
-
-    var body: some View {
-        VStack(spacing: 0) {
-            ScrollView {
-                VStack(alignment: .leading, spacing: 0) {
-                    Text("Private Discriminator")
-                        .font(.system(size: 24, weight: .semibold))
-                        .padding(.bottom, 18)
-
-                    SettingsRow(
-                        title: "Enable",
-                        message: "Resolve Swift private-discriminator hashes from imported module CSVs. Disabled by default.",
-                        controlWidth: 84
-                    ) {
-                        Toggle(
-                            "",
-                            isOn: Binding(
-                                get: { store.featureEnabled },
-                                set: { store.setFeatureEnabled($0) }
-                            )
-                        )
-                        .toggleStyle(.switch)
-                    }
-
-                    SettingsDivider()
-
-                    SettingsRow(
-                        title: "Default Library",
-                        message: "Download SwiftUI and SwiftUICore indexes from GitHub into local imported CSVs.",
-                        controlWidth: 190
-                    ) {
-                        Button {
-                            importError = nil
-                            store.updateDefaultLibrary()
-                        } label: {
-                            if store.isUpdatingDefaultLibrary {
-                                Label("Updating…", systemImage: "arrow.down.circle")
-                            } else {
-                                Label("Update Default Library", systemImage: "arrow.down.circle")
-                            }
-                        }
-                        .disabled(store.isUpdatingDefaultLibrary)
-                    }
-
-                    if let message = store.lastDefaultLibraryUpdateMessage {
-                        HStack(spacing: 8) {
-                            if store.isUpdatingDefaultLibrary {
-                                ProgressView()
-                                    .controlSize(.small)
-                            }
-                            Text(message)
-                                .font(.system(size: 11))
-                                .foregroundStyle(.secondary)
-                                .fixedSize(horizontal: false, vertical: true)
-                        }
-                        .padding(.top, -5)
-                        .padding(.bottom, 13)
-                    }
-
-                    if store.featureEnabled {
-                        SettingsDivider()
-
-                        SettingsRow(
-                            title: "Autosave",
-                            message: "Allow future guessed rows to use autosaved module CSVs.",
-                            controlWidth: 84
-                        ) {
-                            Toggle(
-                                "",
-                                isOn: Binding(
-                                    get: { store.autosaveEnabled },
-                                    set: { store.setAutosaveEnabled($0) }
-                                )
-                            )
-                            .toggleStyle(.switch)
-                        }
-
-                        VStack(alignment: .leading, spacing: 10) {
-                            HStack(spacing: 8) {
-                                Button {
-                                    beginImport()
-                                } label: {
-                                    Label("Import Module", systemImage: "square.and.arrow.down")
-                                }
-
-                                Button {
-                                    store.revealStorageDirectory()
-                                } label: {
-                                    Label("Reveal Storage", systemImage: "folder")
-                                }
-
-                                Spacer()
-                            }
-
-                            if store.moduleStatuses.isEmpty {
-                                Text("No modules imported yet.")
-                                    .font(.system(size: 12))
-                                    .foregroundStyle(.secondary)
-                            } else {
-                                VStack(spacing: 0) {
-                                    ForEach(store.moduleStatuses) { status in
-                                        ModuleStatusRow(status: status, store: store) { message in
-                                            importError = message
-                                        }
-
-                                        if status.id != store.moduleStatuses.last?.id {
-                                            Divider()
-                                        }
-                                    }
-                                }
-                            }
-
-                            diagnosticsView
-                            errorView
-                        }
-                        .padding(.vertical, 13)
-                    }
-                }
-                .padding(.horizontal, 32)
-                .padding(.top, 28)
-                .padding(.bottom, 24)
-            }
-
-            Divider()
-
-            HStack {
-                Spacer()
-                Button("Done") {
-                    NSApp.keyWindow?.performClose(nil)
-                }
-                .keyboardShortcut(.defaultAction)
-            }
-            .padding(.horizontal, 24)
-            .padding(.vertical, 14)
-            .background(.bar)
-        }
-        .frame(minWidth: 640, idealWidth: 660, minHeight: 520, idealHeight: 640)
-        .background(Color(nsColor: .windowBackgroundColor))
-        .onAppear {
-            store.reloadFromDisk()
-        }
-    }
-
-    @ViewBuilder
-    private var diagnosticsView: some View {
-        if !store.invalidDiagnostics.isEmpty {
-            VStack(alignment: .leading, spacing: 4) {
-                Text("Invalid CSV Diagnostics")
-                    .font(.system(size: 12, weight: .medium))
-                ForEach(store.invalidDiagnostics) { diagnostic in
-                    Text("\(diagnostic.module) \(diagnostic.source): \(diagnostic.message)")
-                        .font(.system(size: 11))
-                        .foregroundStyle(.red)
-                        .fixedSize(horizontal: false, vertical: true)
-                }
-            }
-        }
-    }
-
-    @ViewBuilder
-    private var errorView: some View {
-        if let importError {
-            Text(importError)
-                .font(.system(size: 11))
-                .foregroundStyle(.red)
-                .fixedSize(horizontal: false, vertical: true)
-        } else if let error = store.lastSettingsError {
-            Text(error)
-                .font(.system(size: 11))
-                .foregroundStyle(.red)
-                .fixedSize(horizontal: false, vertical: true)
-        }
-    }
-
-    private func beginImport() {
-        importError = nil
-        guard let module = promptForModuleName() else {
-            return
-        }
-
-        let panel = NSOpenPanel()
-        panel.canChooseDirectories = true
-        panel.canChooseFiles = false
-        panel.allowsMultipleSelection = false
-        panel.prompt = NSLocalizedString("Import", comment: "")
-        panel.message = String(
-            format: NSLocalizedString("Choose the local Swift source folder for %@.", comment: ""),
-            module
-        )
-
-        guard panel.runModal() == .OK, let url = panel.url else {
-            return
-        }
-
-        do {
-            try store.importModule(named: module, from: url)
-        } catch {
-            importError = error.localizedDescription
-        }
-    }
-
-    private func promptForModuleName() -> String? {
-        let alert = NSAlert()
-        alert.messageText = NSLocalizedString("Import Private Discriminator Module", comment: "")
-        alert.informativeText = NSLocalizedString("Enter the Swift module name for this source folder.", comment: "")
-        alert.addButton(withTitle: NSLocalizedString("Continue", comment: ""))
-        alert.addButton(withTitle: NSLocalizedString("Cancel", comment: ""))
-
-        let textField = NSTextField(frame: NSRect(x: 0, y: 0, width: 280, height: 24))
-        textField.placeholderString = NSLocalizedString("ModuleName", comment: "")
-        alert.accessoryView = textField
-
-        guard alert.runModal() == .alertFirstButtonReturn else {
-            return nil
-        }
-
-        let module = textField.stringValue.trimmingCharacters(in: .whitespacesAndNewlines)
-        if module.isEmpty {
-            importError = NSLocalizedString("Module name is required.", comment: "")
-            return nil
-        }
-        return module
-    }
-}
-
-private struct SettingsRow<Control: View>: View {
-    let title: LocalizedStringKey
-    let message: LocalizedStringKey?
-    let controlWidth: CGFloat
-    @ViewBuilder let control: Control
-
-    var body: some View {
-        HStack(alignment: .firstTextBaseline, spacing: 24) {
-            VStack(alignment: .leading, spacing: 5) {
-                Text(title)
-                    .font(.system(size: 13, weight: .medium))
-                    .foregroundStyle(.primary)
-
-                if let message {
-                    Text(message)
-                        .font(.system(size: 12))
-                        .foregroundStyle(.secondary)
-                        .fixedSize(horizontal: false, vertical: true)
-                }
-            }
-            .frame(maxWidth: .infinity, alignment: .leading)
-
-            control
-                .labelsHidden()
-                .frame(width: controlWidth, alignment: .trailing)
-        }
-        .padding(.vertical, 13)
-    }
-}
-
-private struct SettingsDivider: View {
-    var body: some View {
-        Divider()
-    }
-}
-
-private struct ModuleStatusRow: View {
-    let status: PrivateDiscriminatorModuleStatus
-    let store: PrivateDiscriminatorStore
-    let onError: (String) -> Void
-
-    var body: some View {
-        HStack(alignment: .center, spacing: 10) {
-            Toggle(
-                "",
-                isOn: Binding(
-                    get: { status.isEnabled },
-                    set: { store.setModule(status.module, enabled: $0) }
-                )
-            )
-            .labelsHidden()
-            .toggleStyle(.switch)
-
-            VStack(alignment: .leading, spacing: 3) {
-                Text(status.module)
-                    .font(.system(size: 13, weight: .medium))
-
-                Text(status.sourceSummary)
-                    .font(.system(size: 11))
-                    .foregroundStyle(.secondary)
-
-                if let diagnostic = status.diagnostic {
-                    Text(diagnostic)
-                        .font(.system(size: 11))
-                        .foregroundStyle(.red)
-                        .fixedSize(horizontal: false, vertical: true)
-                }
-            }
-
-            Spacer(minLength: 8)
-
-            Button {
-                reimport()
-            } label: {
-                Image(systemName: "arrow.clockwise")
-            }
-            .buttonStyle(.borderless)
-            .help("Reimport from saved source folder")
-            .disabled(status.sourceFolderPath == nil)
-
-            Button {
-                store.revealModule(status.module)
-            } label: {
-                Image(systemName: "folder")
-            }
-            .buttonStyle(.borderless)
-            .help("Reveal CSV")
-
-            Button(role: .destructive) {
-                remove()
-            } label: {
-                Image(systemName: "trash")
-            }
-            .buttonStyle(.borderless)
-            .help("Remove module CSVs")
-        }
-        .padding(.vertical, 8)
-    }
-
-    private func reimport() {
-        do {
-            try store.reimportModule(status.module)
-        } catch {
-            onError(error.localizedDescription)
-        }
-    }
-
-    private func remove() {
-        let alert = NSAlert()
-        alert.messageText = String(
-            format: NSLocalizedString("Remove %@?", comment: ""),
-            status.module
-        )
-        alert.informativeText = NSLocalizedString("This removes imported and autosaved CSVs for the module.", comment: "")
-        alert.addButton(withTitle: NSLocalizedString("Remove", comment: ""))
-        alert.addButton(withTitle: NSLocalizedString("Cancel", comment: ""))
-        alert.alertStyle = .warning
-
-        guard alert.runModal() == .alertFirstButtonReturn else {
-            return
-        }
-
-        do {
-            try store.removeModule(status.module)
-        } catch {
-            onError(error.localizedDescription)
-        }
-    }
-}
diff --git a/LookInside/PrivateDiscriminator/PrivateDiscriminatorStore.swift b/LookInside/PrivateDiscriminator/PrivateDiscriminatorStore.swift
index b344c357..cc6ca15d 100644
--- a/LookInside/PrivateDiscriminator/PrivateDiscriminatorStore.swift
+++ b/LookInside/PrivateDiscriminator/PrivateDiscriminatorStore.swift
@@ -1008,6 +1008,11 @@ final class PrivateDiscriminatorStore: NSObject {
         DefaultLibraryModule(name: "SwiftUICore"),
     ]
 
+    /// The modules the default library holds, in the order they download.
+    static var defaultLibraryModuleNames: [String] {
+        defaultLibraryModules.map(\.name)
+    }
+
     private func promptForModuleName(defaultModule: String?, window _: NSWindow?) -> String? {
         let alert = NSAlert()
         alert.messageText = NSLocalizedString("Import Private Discriminator Module", comment: "")
diff --git a/LookInside/Settings/GeneralSettingsPage.swift b/LookInside/Settings/GeneralSettingsPage.swift
new file mode 100644
index 00000000..b00f2672
--- /dev/null
+++ b/LookInside/Settings/GeneralSettingsPage.swift
@@ -0,0 +1,420 @@
+//
+//  GeneralSettingsPage.swift
+//  LookInside
+//
+//  The General page of the Settings window: what the Preferences window
+//  used to hold. PreferenceManager.shared still owns every value here and
+//  stores it in the standard user defaults under its original key.
+//
+
+import AppKit
+import Foundation
+import LookInsideHostCore
+import SwiftUI
+import UIFoundationSettingsUI
+
+struct GeneralSettingsPage: View {
+    let model: GeneralSettingsModel
+
+    var body: some View {
+        SettingsForm {
+            GeneralAppearanceSection(model: model)
+            GeneralColorFormatSection(model: model)
+            GeneralImageContrastSection(model: model)
+            GeneralHierarchySection(model: model)
+            GeneralTimeoutSection(model: model)
+            #if DEBUG
+                GeneralLicenseTimeoutSection(model: model)
+            #endif
+            GeneralResetSection(model: model)
+        }
+    }
+}
+
+/// Dark, light, or whichever the system uses: picked from the pictures
+/// System Settings shows for the same choice, or from a menu when this
+/// macOS does not have them where they are looked for.
+private struct GeneralAppearanceSection: View {
+    @Bindable var model: GeneralSettingsModel
+
+    var body: some View {
+        Section {
+            if let thumbnails = SystemAppearanceThumbnails.current {
+                LabeledContent("Appearance") {
+                    AppearanceThumbnailPicker(selection: $model.appearanceType, thumbnails: thumbnails)
+                }
+            } else {
+                Picker("Appearance", selection: $model.appearanceType) {
+                    Text("Dark Mode").tag(PreferredAppearanceType.dark)
+                    Text("Light Mode").tag(PreferredAppearanceType.light)
+                    Text("System Default").tag(PreferredAppearanceType.system)
+                }
+            }
+        }
+    }
+}
+
+/// How colors are written out: RGBA components or a hex string.
+private struct GeneralColorFormatSection: View {
+    @Bindable var model: GeneralSettingsModel
+
+    var body: some View {
+        Section {
+            LabeledContent("Color Format") {
+                Picker("Color Format", selection: $model.usesRGBAColorFormat) {
+                    Text(verbatim: "RGBA").tag(true)
+                    Text(verbatim: "HEX").tag(false)
+                }
+                .pickerStyle(.segmented)
+                .labelsHidden()
+                .fixedSize()
+            }
+        } header: {
+            Text("Display")
+        } footer: {
+            Text(colorFormatDescription)
+        }
+    }
+
+    private var colorFormatDescription: LocalizedStringResource {
+        model.usesRGBAColorFormat
+            ? "Color will be displayed in format like (255, 12, 34, 0.5). Alpha value is between 0 and 1."
+            : "Color will be displayed in format like #7e7e7eff. The components are #RRGGBBAA."
+    }
+}
+
+/// How deep the selected layer's color is.
+private struct GeneralImageContrastSection: View {
+    @Bindable var model: GeneralSettingsModel
+
+    var body: some View {
+        Section {
+            LabeledContent("Image contrast") {
+                Picker("Image contrast", selection: $model.imageContrastLevel) {
+                    Text("Normal").tag(0)
+                    Text("Medium").tag(1)
+                    Text("High").tag(2)
+                }
+                .pickerStyle(.segmented)
+                .labelsHidden()
+                .fixedSize()
+            }
+        } footer: {
+            Text("Adjust this option to use a deeper layer selection color.")
+        }
+    }
+}
+
+/// What a double click does in the hierarchy, and whether its expansion
+/// state is kept per app.
+private struct GeneralHierarchySection: View {
+    @Bindable var model: GeneralSettingsModel
+
+    var body: some View {
+        Section {
+            Picker("Double click", selection: $model.doubleClickBehavior) {
+                Text("Expand or collapse layer").tag(DoubleClickBehavior.collapse)
+                Text("Focus on layer").tag(DoubleClickBehavior.focus)
+            }
+
+            Toggle("Remember expansion state per app", isOn: $model.remembersExpansionState)
+        } header: {
+            Text("Hierarchy")
+        } footer: {
+            Text("When on, the hierarchy expand/collapse state is restored per target-app bundle id across host and target-app restarts. The 20 most recently inspected apps are kept; toggling off preserves existing data but stops reading or writing it.")
+        }
+    }
+}
+
+/// How long the hierarchy requests may take.
+private struct GeneralTimeoutSection: View {
+    @Bindable var model: GeneralSettingsModel
+
+    var body: some View {
+        Section {
+            LabeledContent("Hierarchy Timeout") {
+                TimeoutStepper("Hierarchy Timeout", seconds: $model.hierarchyRequestTimeout)
+            }
+        } header: {
+            Text("Timeouts")
+        } footer: {
+            Text("Timeout for hierarchy and hierarchy-details requests, in seconds. Default: 15s.")
+        }
+    }
+}
+
+#if DEBUG
+    /// The license handshake's timeout, there for debugging the handshake.
+    private struct GeneralLicenseTimeoutSection: View {
+        @Bindable var model: GeneralSettingsModel
+
+        var body: some View {
+            Section {
+                LabeledContent("License Timeout") {
+                    TimeoutStepper("License Timeout", seconds: $model.licenseHandshakeTimeout)
+                }
+            } footer: {
+                Text("Timeout for license challenge and verification requests, in seconds. Default: 5s.")
+            }
+        }
+    }
+#endif
+
+/// Putting every setting on this page back to its default, laid out the
+/// way Xcode's settings offer the same.
+private struct GeneralResetSection: View {
+    let model: GeneralSettingsModel
+
+    var body: some View {
+        Section {
+            // An HStack rather than LabeledContent, which would line the
+            // button up with the title alone instead of centering it on
+            // both lines.
+            HStack {
+                VStack(alignment: .leading, spacing: 2) {
+                    Text("Reset Settings")
+                        .font(.headline)
+                    Text("Resets the settings on this page to their default values.")
+                        .font(.subheadline)
+                        .foregroundStyle(.secondary)
+                        .fixedSize(horizontal: false, vertical: true)
+                }
+
+                Spacer()
+
+                Button("Reset", role: .destructive) {
+                    model.resetToDefaults()
+                }
+                .keyboardShortcut(.delete, modifiers: [.command, .shift])
+            }
+        } header: {
+            Text("Reset")
+        }
+    }
+}
+
+/// Seconds, typed into the field or stepped a whole second at a time.
+private struct TimeoutStepper: View {
+    private let title: LocalizedStringKey
+    @Binding private var seconds: Double
+
+    init(_ title: LocalizedStringKey, seconds: Binding<Double>) {
+        self.title = title
+        _seconds = seconds
+    }
+
+    var body: some View {
+        Stepper(
+            title,
+            value: $seconds,
+            in: PreferenceValuePolicy.timeoutRange,
+            step: 1,
+            format: .number.precision(.fractionLength(0 ... 2))
+        )
+        .labelsHidden()
+    }
+}
+
+// MARK: - Appearance thumbnails
+
+/// The pictures System Settings shows for its three appearance choices.
+/// They are Apple's artwork, so the app reads them out of the system's
+/// Appearance settings extension at run time instead of shipping copies.
+private struct SystemAppearanceThumbnails {
+    let system: NSImage
+    let light: NSImage
+    let dark: NSImage
+
+    /// Nil when this version of macOS has moved or renamed the pictures.
+    @MainActor static let current = SystemAppearanceThumbnails(
+        settingsExtensionPath: "/System/Library/ExtensionKit/Extensions/Appearance.appex"
+    )
+
+    init?(settingsExtensionPath: String) {
+        guard
+            let settingsExtension = Bundle(path: settingsExtensionPath),
+            let system = settingsExtension.image(forResource: "AppearanceAuto"),
+            let light = settingsExtension.image(forResource: "AppearanceLight"),
+            let dark = settingsExtension.image(forResource: "AppearanceDark")
+        else {
+            return nil
+        }
+        self.system = system
+        self.light = light
+        self.dark = dark
+    }
+}
+
+/// System, light and dark side by side, the chosen one outlined.
+private struct AppearanceThumbnailPicker: View {
+    @Binding var selection: PreferredAppearanceType
+    let thumbnails: SystemAppearanceThumbnails
+
+    var body: some View {
+        HStack(spacing: 5) {
+            AppearanceThumbnailOption(image: thumbnails.system, title: "System", isSelected: selection == .system) {
+                selection = .system
+            }
+            AppearanceThumbnailOption(image: thumbnails.light, title: "Light", isSelected: selection == .light) {
+                selection = .light
+            }
+            AppearanceThumbnailOption(image: thumbnails.dark, title: "Dark", isSelected: selection == .dark) {
+                selection = .dark
+            }
+        }
+        .padding(.vertical, 8)
+    }
+}
+
+private struct AppearanceThumbnailOption: View {
+    let image: NSImage
+    let title: LocalizedStringKey
+    let isSelected: Bool
+    let action: () -> Void
+
+    @State private var isHovering = false
+
+    var body: some View {
+        Button(action: action) {
+            VStack(spacing: 8) {
+                Image(nsImage: image)
+                    .resizable()
+                    .aspectRatio(contentMode: .fit)
+                    .frame(width: 72, height: 48)
+                    .clipShape(RoundedRectangle(cornerRadius: 5))
+                    .overlay {
+                        RoundedRectangle(cornerRadius: 5)
+                            .stroke(isSelected ? Color.accentColor : Color.clear, lineWidth: 3)
+                    }
+                    .shadow(color: .black.opacity(isHovering ? 0.15 : 0.1), radius: isHovering ? 3 : 2, x: 0, y: 1)
+
+                Text(title)
+                    .font(.caption)
+                    .foregroundStyle(isSelected ? .primary : .secondary)
+            }
+        }
+        .buttonStyle(.plain)
+        .accessibilityAddTraits(isSelected ? .isSelected : [])
+        .onHover { hovering in
+            isHovering = hovering
+        }
+    }
+}
+
+// MARK: - Model
+
+/// The General page's side of PreferenceManager.shared. Setting a property
+/// writes the manager, and KVO brings every change back, including the ones
+/// made elsewhere (the Dashboard switches the color format too), so the page
+/// never shows a stale value.
+@MainActor
+@Observable
+final class GeneralSettingsModel {
+    private let preferences: PreferenceManager
+    @ObservationIgnored private var observations: [NSKeyValueObservation] = []
+
+    // What the manager holds, as of its last KVO notification.
+    private var currentAppearanceType: PreferredAppearanceType
+    private var currentUsesRGBAColorFormat: Bool
+    private var currentImageContrastLevel: Int
+    private var currentDoubleClickBehavior: DoubleClickBehavior
+    private var currentRemembersExpansionState: Bool
+    private var currentHierarchyRequestTimeout: TimeInterval
+    private var currentLicenseHandshakeTimeout: TimeInterval
+
+    init(preferences: PreferenceManager = .shared) {
+        self.preferences = preferences
+        currentAppearanceType = preferences.appearanceType
+        currentUsesRGBAColorFormat = preferences.rgbaFormat
+        currentImageContrastLevel = preferences.imageContrastLevel
+        currentDoubleClickBehavior = preferences.doubleClickBehavior
+        currentRemembersExpansionState = preferences.rememberExpansionState
+        currentHierarchyRequestTimeout = preferences.hierarchyRequestTimeoutInterval
+        currentLicenseHandshakeTimeout = preferences.licenseHandshakeTimeoutInterval
+
+        observations = [
+            preferences.observe(\.appearanceType, options: [.new]) { [weak self] preferences, _ in
+                MainActor.assumeIsolated { self?.currentAppearanceType = preferences.appearanceType }
+            },
+            preferences.observe(\.rgbaFormat, options: [.new]) { [weak self] preferences, _ in
+                MainActor.assumeIsolated { self?.currentUsesRGBAColorFormat = preferences.rgbaFormat }
+            },
+            preferences.observe(\.imageContrastLevel, options: [.new]) { [weak self] preferences, _ in
+                MainActor.assumeIsolated { self?.currentImageContrastLevel = preferences.imageContrastLevel }
+            },
+            preferences.observe(\.doubleClickBehavior, options: [.new]) { [weak self] preferences, _ in
+                MainActor.assumeIsolated { self?.currentDoubleClickBehavior = preferences.doubleClickBehavior }
+            },
+            preferences.observe(\.rememberExpansionState, options: [.new]) { [weak self] preferences, _ in
+                MainActor.assumeIsolated { self?.currentRemembersExpansionState = preferences.rememberExpansionState }
+            },
+            preferences.observe(\.hierarchyRequestTimeoutInterval, options: [.new]) { [weak self] preferences, _ in
+                MainActor.assumeIsolated { self?.currentHierarchyRequestTimeout = preferences.hierarchyRequestTimeoutInterval }
+            },
+            preferences.observe(\.licenseHandshakeTimeoutInterval, options: [.new]) { [weak self] preferences, _ in
+                MainActor.assumeIsolated { self?.currentLicenseHandshakeTimeout = preferences.licenseHandshakeTimeoutInterval }
+            },
+        ]
+    }
+
+    var appearanceType: PreferredAppearanceType {
+        get { currentAppearanceType }
+        set { preferences.appearanceType = newValue }
+    }
+
+    var usesRGBAColorFormat: Bool {
+        get { currentUsesRGBAColorFormat }
+        set { preferences.rgbaFormat = newValue }
+    }
+
+    var imageContrastLevel: Int {
+        get { currentImageContrastLevel }
+        set { preferences.imageContrastLevel = PreferenceValuePolicy.clampedImageContrastLevel(newValue) }
+    }
+
+    var doubleClickBehavior: DoubleClickBehavior {
+        get { currentDoubleClickBehavior }
+        set { preferences.doubleClickBehavior = newValue }
+    }
+
+    var remembersExpansionState: Bool {
+        get { currentRemembersExpansionState }
+        set { preferences.rememberExpansionState = newValue }
+    }
+
+    var hierarchyRequestTimeout: TimeInterval {
+        get { currentHierarchyRequestTimeout }
+        set {
+            preferences.hierarchyRequestTimeoutInterval = PreferenceValuePolicy.sanitizedTimeout(
+                newValue, defaultValue: defaultHierarchyRequestTimeoutInterval
+            )
+        }
+    }
+
+    var licenseHandshakeTimeout: TimeInterval {
+        get { currentLicenseHandshakeTimeout }
+        set {
+            preferences.licenseHandshakeTimeoutInterval = PreferenceValuePolicy.sanitizedTimeout(
+                newValue, defaultValue: defaultLicenseHandshakeTimeoutInterval
+            )
+        }
+    }
+
+    /// Every value on the page back to its default. Debug builds also forget
+    /// the dismissed tips, as the Preferences window's Reset did.
+    func resetToDefaults() {
+        appearanceType = .system
+        usesRGBAColorFormat = true
+        imageContrastLevel = 0
+        doubleClickBehavior = .collapse
+        remembersExpansionState = true
+        hierarchyRequestTimeout = defaultHierarchyRequestTimeoutInterval
+
+        #if DEBUG
+            licenseHandshakeTimeout = defaultLicenseHandshakeTimeoutInterval
+            MessageManager.sharedInstance().reset()
+            preferences.reset()
+            UserDefaults.standard.removeObject(forKey: "IgnoreFastModeTips")
+        #endif
+    }
+}
diff --git a/LookInside/Settings/PrivateDiscriminatorSettingsPage.swift b/LookInside/Settings/PrivateDiscriminatorSettingsPage.swift
new file mode 100644
index 00000000..81d811b3
--- /dev/null
+++ b/LookInside/Settings/PrivateDiscriminatorSettingsPage.swift
@@ -0,0 +1,333 @@
+//
+//  PrivateDiscriminatorSettingsPage.swift
+//  LookInside
+//
+//  The Private Discriminator page of the Settings window: the feature
+//  switch, the default library download and the imported modules.
+//  PrivateDiscriminatorStore.shared owns all of it and its config.json.
+//
+
+import AppKit
+import SwiftUI
+import UIFoundationSettingsUI
+
+struct PrivateDiscriminatorSettingsPage: View {
+    private let store = PrivateDiscriminatorStore.shared
+
+    /// The last import, reimport or removal failure. It outranks the
+    /// store's own error, which covers loading and saving.
+    @State private var importError: String?
+
+    var body: some View {
+        SettingsForm {
+            PrivateDiscriminatorFeatureSection(store: store)
+            PrivateDiscriminatorDefaultLibrarySection(store: store, importError: $importError)
+
+            if store.featureEnabled {
+                PrivateDiscriminatorAutosaveSection(store: store)
+                PrivateDiscriminatorModulesSection(store: store, importError: $importError)
+                PrivateDiscriminatorProblemsSection(store: store, importError: importError)
+            }
+        }
+        .onAppear {
+            store.reloadFromDisk()
+        }
+    }
+}
+
+/// The feature switch.
+private struct PrivateDiscriminatorFeatureSection: View {
+    @Bindable var store: PrivateDiscriminatorStore
+
+    var body: some View {
+        Section {
+            Toggle("Enable", isOn: $store.isFeatureEnabledSetting)
+        } footer: {
+            Text("Resolve Swift private-discriminator hashes from imported module CSVs. Disabled by default.")
+        }
+    }
+}
+
+/// Downloading the SwiftUI and SwiftUICore indexes, and how the last
+/// download went.
+private struct PrivateDiscriminatorDefaultLibrarySection: View {
+    let store: PrivateDiscriminatorStore
+    @Binding var importError: String?
+
+    var body: some View {
+        Section {
+            // An HStack rather than LabeledContent, so the button stays
+            // centered on the row once the status adds a second line.
+            HStack {
+                VStack(alignment: .leading, spacing: 2) {
+                    Text(PrivateDiscriminatorStore.defaultLibraryModuleNames, format: .list(type: .and))
+
+                    if let message = store.lastDefaultLibraryUpdateMessage {
+                        Text(message)
+                            .font(.subheadline)
+                            .foregroundStyle(.secondary)
+                            .fixedSize(horizontal: false, vertical: true)
+                    }
+                }
+
+                Spacer()
+
+                if store.isUpdatingDefaultLibrary {
+                    ProgressView()
+                        .controlSize(.small)
+                }
+
+                Button {
+                    importError = nil
+                    store.updateDefaultLibrary()
+                } label: {
+                    if store.isUpdatingDefaultLibrary {
+                        Label("Updating…", systemImage: "arrow.down.circle")
+                    } else {
+                        Label("Update Default Library", systemImage: "arrow.down.circle")
+                    }
+                }
+                .disabled(store.isUpdatingDefaultLibrary)
+            }
+        } header: {
+            Text("Default Library")
+        } footer: {
+            Text("Download SwiftUI and SwiftUICore indexes from GitHub into local imported CSVs.")
+        }
+    }
+}
+
+private struct PrivateDiscriminatorAutosaveSection: View {
+    @Bindable var store: PrivateDiscriminatorStore
+
+    var body: some View {
+        Section {
+            Toggle("Autosave", isOn: $store.isAutosaveEnabledSetting)
+        } footer: {
+            Text("Allow future guessed rows to use autosaved module CSVs.")
+        }
+    }
+}
+
+/// Importing a module, and the modules imported so far.
+private struct PrivateDiscriminatorModulesSection: View {
+    let store: PrivateDiscriminatorStore
+    @Binding var importError: String?
+
+    var body: some View {
+        Section {
+            HStack(spacing: 8) {
+                Button {
+                    beginImport()
+                } label: {
+                    Label("Import Module", systemImage: "square.and.arrow.down")
+                }
+
+                Button {
+                    store.revealStorageDirectory()
+                } label: {
+                    Label("Reveal Storage", systemImage: "folder")
+                }
+
+                Spacer()
+            }
+
+            if store.moduleStatuses.isEmpty {
+                Text("No modules imported yet.")
+                    .foregroundStyle(.secondary)
+            } else {
+                ForEach(store.moduleStatuses) { status in
+                    PrivateDiscriminatorModuleRow(status: status, store: store) { message in
+                        importError = message
+                    }
+                }
+            }
+        } header: {
+            Text("Modules")
+        }
+    }
+
+    private func beginImport() {
+        importError = nil
+        guard let module = promptForModuleName() else {
+            return
+        }
+
+        let panel = NSOpenPanel()
+        panel.canChooseDirectories = true
+        panel.canChooseFiles = false
+        panel.allowsMultipleSelection = false
+        panel.prompt = String(localized: "Import")
+        panel.message = String(localized: "Choose the local Swift source folder for \(module).")
+
+        guard panel.runModal() == .OK, let url = panel.url else {
+            return
+        }
+
+        do {
+            try store.importModule(named: module, from: url)
+        } catch {
+            importError = error.localizedDescription
+        }
+    }
+
+    private func promptForModuleName() -> String? {
+        let alert = NSAlert()
+        alert.messageText = String(localized: "Import Private Discriminator Module")
+        alert.informativeText = String(localized: "Enter the Swift module name for this source folder.")
+        alert.addButton(withTitle: String(localized: "Continue"))
+        alert.addButton(withTitle: String(localized: "Cancel"))
+
+        let textField = NSTextField(frame: NSRect(x: 0, y: 0, width: 280, height: 24))
+        textField.placeholderString = String(localized: "ModuleName")
+        alert.accessoryView = textField
+
+        guard alert.runModal() == .alertFirstButtonReturn else {
+            return nil
+        }
+
+        let module = textField.stringValue.trimmingCharacters(in: .whitespacesAndNewlines)
+        if module.isEmpty {
+            importError = String(localized: "Module name is required.")
+            return nil
+        }
+        return module
+    }
+}
+
+/// CSV files that failed to load, and the last error. Each shows only
+/// while there is something to report.
+private struct PrivateDiscriminatorProblemsSection: View {
+    let store: PrivateDiscriminatorStore
+    let importError: String?
+
+    var body: some View {
+        if !store.invalidDiagnostics.isEmpty {
+            Section {
+                ForEach(store.invalidDiagnostics) { diagnostic in
+                    Text("\(diagnostic.module) \(diagnostic.source): \(diagnostic.message)")
+                        .font(.subheadline)
+                        .foregroundStyle(.red)
+                        .fixedSize(horizontal: false, vertical: true)
+                }
+            } header: {
+                Text("Invalid CSV Diagnostics")
+            }
+        }
+
+        if let errorMessage {
+            Section {
+                Text(errorMessage)
+                    .font(.subheadline)
+                    .foregroundStyle(.red)
+                    .fixedSize(horizontal: false, vertical: true)
+            }
+        }
+    }
+
+    private var errorMessage: String? {
+        importError ?? store.lastSettingsError
+    }
+}
+
+private struct PrivateDiscriminatorModuleRow: View {
+    let status: PrivateDiscriminatorModuleStatus
+    @Bindable var store: PrivateDiscriminatorStore
+    let onError: (String) -> Void
+
+    var body: some View {
+        HStack(alignment: .center, spacing: 10) {
+            Toggle(status.module, isOn: $store[isModuleEnabled: status.module])
+                .labelsHidden()
+                .toggleStyle(.switch)
+
+            VStack(alignment: .leading, spacing: 3) {
+                Text(status.module)
+
+                Text(status.sourceSummary)
+                    .font(.subheadline)
+                    .foregroundStyle(.secondary)
+
+                if let diagnostic = status.diagnostic {
+                    Text(diagnostic)
+                        .font(.subheadline)
+                        .foregroundStyle(.red)
+                        .fixedSize(horizontal: false, vertical: true)
+                }
+            }
+
+            Spacer(minLength: 8)
+
+            Button {
+                reimport()
+            } label: {
+                Image(systemName: "arrow.clockwise")
+            }
+            .buttonStyle(.borderless)
+            .help("Reimport from saved source folder")
+            .disabled(status.sourceFolderPath == nil)
+
+            Button {
+                store.revealModule(status.module)
+            } label: {
+                Image(systemName: "folder")
+            }
+            .buttonStyle(.borderless)
+            .help("Reveal CSV")
+
+            Button(role: .destructive) {
+                remove()
+            } label: {
+                Image(systemName: "trash")
+            }
+            .buttonStyle(.borderless)
+            .help("Remove module CSVs")
+        }
+    }
+
+    private func reimport() {
+        do {
+            try store.reimportModule(status.module)
+        } catch {
+            onError(error.localizedDescription)
+        }
+    }
+
+    private func remove() {
+        let alert = NSAlert()
+        alert.messageText = String(localized: "Remove \(status.module)?")
+        alert.informativeText = String(localized: "This removes imported and autosaved CSVs for the module.")
+        alert.addButton(withTitle: String(localized: "Remove"))
+        alert.addButton(withTitle: String(localized: "Cancel"))
+        alert.alertStyle = .warning
+
+        guard alert.runModal() == .alertFirstButtonReturn else {
+            return
+        }
+
+        do {
+            try store.removeModule(status.module)
+        } catch {
+            onError(error.localizedDescription)
+        }
+    }
+}
+
+/// The store's switches as read-write properties, so the page can bind them
+/// by key path; writing one saves config.json and reloads the store.
+private extension PrivateDiscriminatorStore {
+    var isFeatureEnabledSetting: Bool {
+        get { featureEnabled }
+        set { setFeatureEnabled(newValue) }
+    }
+
+    var isAutosaveEnabledSetting: Bool {
+        get { autosaveEnabled }
+        set { setAutosaveEnabled(newValue) }
+    }
+
+    subscript(isModuleEnabled module: String) -> Bool {
+        get { moduleStatuses.first { $0.module == module }?.isEnabled ?? false }
+        set { setModule(module, enabled: newValue) }
+    }
+}
diff --git a/LookInside/Settings/SettingsPages.swift b/LookInside/Settings/SettingsPages.swift
new file mode 100644
index 00000000..8b1f609e
--- /dev/null
+++ b/LookInside/Settings/SettingsPages.swift
@@ -0,0 +1,49 @@
+//
+//  SettingsPages.swift
+//  LookInside
+//
+//  The pages of the Settings window, which is UIFoundation's
+//  SettingsWindowController (NavigationManager holds it). The window only
+//  changes how the settings are shown: PreferenceManager keeps the general
+//  ones in the standard user defaults, PrivateDiscriminatorStore keeps its
+//  own in config.json.
+//
+//  The pages are laid out the way RuntimeViewer lays out its settings with
+//  the same window: plain glyphs in the sidebar, a header over each group,
+//  and what a setting does in the footer under its group.
+//
+
+import SwiftUI
+import UIFoundationSettingsUI
+
+enum SettingsPages {
+    /// Page identifiers. Unlike the titles they do not change with the
+    /// language, so they are what selects a page.
+    static let generalIdentifier = "general"
+    static let privateDiscriminatorIdentifier = "privateDiscriminator"
+
+    /// The sidebar, in order.
+    @MainActor
+    @SettingsPageBuilder
+    static func make() -> [SettingsPage] {
+        // Made once per window, so the page keeps one model however often
+        // SwiftUI rebuilds it.
+        let generalModel = GeneralSettingsModel()
+
+        SettingsPage(
+            String(localized: "General", comment: "Title of the Settings window's General page."),
+            id: generalIdentifier,
+            plainSymbol: "gearshape"
+        ) {
+            GeneralSettingsPage(model: generalModel)
+        }
+
+        SettingsPage(
+            String(localized: "Private Discriminator", comment: "Title of the Settings window's Private Discriminator page."),
+            id: privateDiscriminatorIdentifier,
+            plainSymbol: "number"
+        ) {
+            PrivateDiscriminatorSettingsPage()
+        }
+    }
+}
diff --git a/LookInside/Toolbar/MenuPopoverSettingController.swift b/LookInside/Toolbar/MenuPopoverSettingController.swift
index cf38032b..632203eb 100644
--- a/LookInside/Toolbar/MenuPopoverSettingController.swift
+++ b/LookInside/Toolbar/MenuPopoverSettingController.swift
@@ -133,7 +133,7 @@ final class MenuPopoverSettingController: BaseViewController {
     }
 
     @objc private func handlePreferenceButton() {
-        NavigationManager.shared.showPreference()
+        NavigationManager.shared.showSettings()
     }
 
     @objc private func handleZInterspaceDidChange(_ param: MessageActionParameters) {
diff --git a/Packages/LookInsideHostCore/Sources/LookInsideHostCore/PreferenceValuePolicy.swift b/Packages/LookInsideHostCore/Sources/LookInsideHostCore/PreferenceValuePolicy.swift
new file mode 100644
index 00000000..11e6ea51
--- /dev/null
+++ b/Packages/LookInsideHostCore/Sources/LookInsideHostCore/PreferenceValuePolicy.swift
@@ -0,0 +1,31 @@
+//
+//  PreferenceValuePolicy.swift
+//  LookInsideHostCore
+//
+//  The ranges the Settings window keeps user-entered preference values in,
+//  before the app target writes them to its PreferenceManager.
+//
+
+/// What the Settings window stores for a value the user entered.
+public enum PreferenceValuePolicy {
+    /// Request timeouts, in seconds.
+    public static let timeoutRange: ClosedRange<Double> = 0.1 ... 120
+
+    /// Image contrast levels: normal, medium and high.
+    public static let imageContrastLevelRange: ClosedRange<Int> = 0 ... 2
+
+    /// A typed timeout moved into `timeoutRange`. A value that is not
+    /// finite, or not above 0, means nothing usable was entered, so it
+    /// falls back to `defaultValue` instead.
+    public static func sanitizedTimeout(_ value: Double, defaultValue: Double) -> Double {
+        guard value.isFinite, value > 0 else {
+            return defaultValue
+        }
+        return min(max(value, timeoutRange.lowerBound), timeoutRange.upperBound)
+    }
+
+    /// A contrast level moved into `imageContrastLevelRange`.
+    public static func clampedImageContrastLevel(_ level: Int) -> Int {
+        min(max(level, imageContrastLevelRange.lowerBound), imageContrastLevelRange.upperBound)
+    }
+}
diff --git a/Packages/LookInsideHostCore/Tests/LookInsideHostCoreTests/PreferenceValuePolicyTests.swift b/Packages/LookInsideHostCore/Tests/LookInsideHostCoreTests/PreferenceValuePolicyTests.swift
new file mode 100644
index 00000000..1920e8da
--- /dev/null
+++ b/Packages/LookInsideHostCore/Tests/LookInsideHostCoreTests/PreferenceValuePolicyTests.swift
@@ -0,0 +1,28 @@
+@testable import LookInsideHostCore
+import Testing
+
+struct PreferenceValuePolicyTests {
+    @Test(arguments: [
+        (typed: 15.0, stored: 15.0),
+        (typed: 0.05, stored: 0.1),
+        (typed: 500, stored: 120),
+        (typed: 0, stored: 7),
+        (typed: -3, stored: 7),
+        (typed: .nan, stored: 7),
+        (typed: .infinity, stored: 7),
+    ])
+    func aTypedTimeoutIsKeptBetweenATenthOfASecondAndTwoMinutes(typed: Double, stored: Double) {
+        #expect(PreferenceValuePolicy.sanitizedTimeout(typed, defaultValue: 7) == stored)
+    }
+
+    @Test(arguments: [
+        (chosen: -1, stored: 0),
+        (chosen: 0, stored: 0),
+        (chosen: 1, stored: 1),
+        (chosen: 2, stored: 2),
+        (chosen: 5, stored: 2),
+    ])
+    func theImageContrastLevelStaysBetweenNormalAndHigh(chosen: Int, stored: Int) {
+        #expect(PreferenceValuePolicy.clampedImageContrastLevel(chosen) == stored)
+    }
+}