diff --git a/bin/internal/engine.version b/bin/internal/engine.version
index b913705..9c1fbfe 100644
--- a/bin/internal/engine.version
+++ b/bin/internal/engine.version
@@ -1 +1 @@
-63ca99584a1aef79722b2a7c6414570b54416bab
+74b74b10ea6764e373ca2bcb420fdb4a6f6b5918
diff --git a/packages/flutter/lib/src/rendering/layer.dart b/packages/flutter/lib/src/rendering/layer.dart
index d56f4aa..868bd5a 100644
--- a/packages/flutter/lib/src/rendering/layer.dart
+++ b/packages/flutter/lib/src/rendering/layer.dart
@@ -1763,11 +1763,16 @@
   @override
   void addToScene(ui.SceneBuilder builder) {
     assert(alpha != null);
-    bool enabled = firstChild != null;  // don't add this layer if there's no child
+
+    // Don't add this layer if there's no child.
+    bool enabled = firstChild != null;
     if (!enabled) {
+      // Ensure the engineLayer is disposed.
+      engineLayer = null;
       // TODO(dnfield): Remove this if/when we can fix https://github.com/flutter/flutter/issues/90004
       return;
     }
+
     assert(() {
       enabled = enabled && !debugDisableOpacityLayers;
       return true;
diff --git a/packages/flutter/lib/src/services/raw_keyboard.dart b/packages/flutter/lib/src/services/raw_keyboard.dart
index 515261d..188b1e8 100644
--- a/packages/flutter/lib/src/services/raw_keyboard.dart
+++ b/packages/flutter/lib/src/services/raw_keyboard.dart
@@ -280,10 +280,14 @@
   const RawKeyEvent({
     required this.data,
     this.character,
+    this.repeat = false,
   });
 
   /// Creates a concrete [RawKeyEvent] class from a message in the form received
   /// on the [SystemChannels.keyEvent] channel.
+  ///
+  /// [RawKeyEvent.repeat] will be derived from the current keyboard state,
+  /// instead of using the message information.
   factory RawKeyEvent.fromMessage(Map<String, Object?> message) {
     String? character;
     RawKeyEventData _dataFromWeb() {
@@ -388,10 +392,11 @@
           throw FlutterError('Unknown keymap for key events: $keymap');
       }
     }
+    final bool repeat = RawKeyboard.instance.physicalKeysPressed.contains(data.physicalKey);
     final String type = message['type']! as String;
     switch (type) {
       case 'keydown':
-        return RawKeyDownEvent(data: data, character: character);
+        return RawKeyDownEvent(data: data, character: character, repeat: repeat);
       case 'keyup':
         return RawKeyUpEvent(data: data);
       default:
@@ -504,6 +509,15 @@
   /// input.
   final String? character;
 
+  /// Whether this is a repeated down event.
+  ///
+  /// When a key is held down, the systems usually fire a down event and then
+  /// a series of repeated down events. The [repeat] is false for the
+  /// first event and true for the following events.
+  ///
+  /// The [repeat] attribute is always false for [RawKeyUpEvent]s.
+  final bool repeat;
+
   /// Platform-specific information about the key event.
   final RawKeyEventData data;
 
@@ -512,6 +526,8 @@
     super.debugFillProperties(properties);
     properties.add(DiagnosticsProperty<LogicalKeyboardKey>('logicalKey', logicalKey));
     properties.add(DiagnosticsProperty<PhysicalKeyboardKey>('physicalKey', physicalKey));
+    if (this is RawKeyDownEvent)
+      properties.add(DiagnosticsProperty<bool>('repeat', repeat));
   }
 }
 
@@ -525,7 +541,8 @@
   const RawKeyDownEvent({
     required RawKeyEventData data,
     String? character,
-  }) : super(data: data, character: character);
+    bool repeat = false,
+  }) : super(data: data, character: character, repeat: repeat);
 }
 
 /// The user has released a key on the keyboard.
@@ -538,7 +555,7 @@
   const RawKeyUpEvent({
     required RawKeyEventData data,
     String? character,
-  }) : super(data: data, character: character);
+  }) : super(data: data, character: character, repeat: false);
 }
 
 /// A callback type used by [RawKeyboard.keyEventHandler] to send key events to
diff --git a/packages/flutter/lib/src/widgets/shortcuts.dart b/packages/flutter/lib/src/widgets/shortcuts.dart
index 7dcedeb..9f1b5e9 100644
--- a/packages/flutter/lib/src/widgets/shortcuts.dart
+++ b/packages/flutter/lib/src/widgets/shortcuts.dart
@@ -388,8 +388,7 @@
 ///  * [CharacterActivator], an activator that represents key combinations
 ///    that result in the specified character, such as question mark.
 class SingleActivator with Diagnosticable implements ShortcutActivator {
-  /// Triggered when the [trigger] key is pressed or repeated when the
-  /// modifiers are held.
+  /// Triggered when the [trigger] key is pressed while the modifiers are held.
   ///
   /// The `trigger` should be the non-modifier key that is pressed after all the
   /// modifiers, such as [LogicalKeyboardKey.keyC] as in `Ctrl+C`. It must not be
@@ -398,8 +397,9 @@
   /// The `control`, `shift`, `alt`, and `meta` flags represent whether
   /// the respect modifier keys should be held (true) or released (false)
   ///
-  /// On each [RawKeyDownEvent] of the [trigger] key, this activator checks
-  /// whether the specified modifier conditions are met.
+  /// By default, the activator is checked on all [RawKeyDownEvent] events for
+  /// the [trigger] key. If `includeRepeats` is false, only the [trigger] key
+  /// events with a false [RawKeyDownEvent.repeat] attribute will be considered.
   ///
   /// {@tool dartpad}
   /// In the following example, the shortcut `Control + C` increases the counter:
@@ -412,6 +412,7 @@
     this.shift = false,
     this.alt = false,
     this.meta = false,
+    this.includeRepeats = true,
   }) : // The enumerated check with `identical` is cumbersome but the only way
        // since const constructors can not call functions such as `==` or
        // `Set.contains`. Checking with `identical` might not work when the
@@ -482,6 +483,14 @@
   ///  * [LogicalKeyboardKey.metaLeft], [LogicalKeyboardKey.metaRight].
   final bool meta;
 
+  /// Whether this activator accepts repeat events of the [trigger] key.
+  ///
+  /// If [includeRepeats] is true, the activator is checked on all
+  /// [RawKeyDownEvent] events for the [trigger] key. If `includeRepeats` is
+  /// false, only the [trigger] key events with a false [RawKeyDownEvent.repeat]
+  /// attribute will be considered.
+  final bool includeRepeats;
+
   @override
   Iterable<LogicalKeyboardKey> get triggers {
     return <LogicalKeyboardKey>[trigger];
@@ -491,6 +500,7 @@
   bool accepts(RawKeyEvent event, RawKeyboard state) {
     final Set<LogicalKeyboardKey> pressed = state.keysPressed;
     return event is RawKeyDownEvent
+      && (includeRepeats || !event.repeat)
       && (control == (pressed.contains(LogicalKeyboardKey.controlLeft) || pressed.contains(LogicalKeyboardKey.controlRight)))
       && (shift == (pressed.contains(LogicalKeyboardKey.shiftLeft) || pressed.contains(LogicalKeyboardKey.shiftRight)))
       && (alt == (pressed.contains(LogicalKeyboardKey.altLeft) || pressed.contains(LogicalKeyboardKey.altRight)))
@@ -522,6 +532,7 @@
   void debugFillProperties(DiagnosticPropertiesBuilder properties) {
     super.debugFillProperties(properties);
     properties.add(DiagnosticsProperty<String>('keys', debugDescribeKeys()));
+    properties.add(FlagProperty('includeRepeats', value: includeRepeats, ifFalse: 'excluding repeats'));
   }
 }
 
diff --git a/packages/flutter/test/rendering/layers_test.dart b/packages/flutter/test/rendering/layers_test.dart
index 8d4e2dc..1d9aa4a 100644
--- a/packages/flutter/test/rendering/layers_test.dart
+++ b/packages/flutter/test/rendering/layers_test.dart
@@ -637,6 +637,21 @@
     expect(builder.addedPicture, true);
     expect(layer.engineLayer, isA<FakeOpacityEngineLayer>());
   });
+
+  test('OpacityLayer dispose its engineLayer if there are no children', () {
+    final OpacityLayer layer = OpacityLayer(alpha: 128);
+    final FakeSceneBuilder builder = FakeSceneBuilder();
+    layer.addToScene(builder);
+    expect(layer.engineLayer, null);
+
+    layer.append(PictureLayer(Rect.largest)..picture = FakePicture());
+    layer.addToScene(builder);
+    expect(layer.engineLayer, isA<FakeOpacityEngineLayer>());
+
+    layer.removeAllChildren();
+    layer.addToScene(builder);
+    expect(layer.engineLayer, null);
+  });
 }
 
 class FakeEngineLayer extends Fake implements EngineLayer {
diff --git a/packages/flutter/test/services/raw_keyboard_test.dart b/packages/flutter/test/services/raw_keyboard_test.dart
index 8a7703d..c55d616 100644
--- a/packages/flutter/test/services/raw_keyboard_test.dart
+++ b/packages/flutter/test/services/raw_keyboard_test.dart
@@ -598,6 +598,49 @@
       );
     }, skip: isBrowser); // [intended] This is an iOS-specific test.
 
+    testWidgets('repeat events', (WidgetTester tester) async {
+      expect(RawKeyboard.instance.keysPressed, isEmpty);
+      late RawKeyEvent receivedEvent;
+      RawKeyboard.instance.keyEventHandler = (RawKeyEvent event) {
+        receivedEvent = event;
+        return true;
+      };
+
+      // Dispatch a down event.
+      final Map<String, dynamic> downData = KeyEventSimulator.getKeyData(
+        LogicalKeyboardKey.keyA,
+        platform: 'windows',
+      );
+      await ServicesBinding.instance?.defaultBinaryMessenger.handlePlatformMessage(
+        SystemChannels.keyEvent.name,
+        SystemChannels.keyEvent.codec.encodeMessage(downData),
+        (ByteData? data) {},
+      );
+      expect(receivedEvent.repeat, false);
+
+      // Dispatch another down event, which should be recognized as a repeat.
+      await ServicesBinding.instance?.defaultBinaryMessenger.handlePlatformMessage(
+        SystemChannels.keyEvent.name,
+        SystemChannels.keyEvent.codec.encodeMessage(downData),
+        (ByteData? data) {},
+      );
+      expect(receivedEvent.repeat, true);
+
+      // Dispatch an up event.
+      await ServicesBinding.instance?.defaultBinaryMessenger.handlePlatformMessage(
+        SystemChannels.keyEvent.name,
+        SystemChannels.keyEvent.codec.encodeMessage(KeyEventSimulator.getKeyData(
+          LogicalKeyboardKey.keyA,
+          isDown: false,
+          platform: 'windows',
+        )),
+        (ByteData? data) {},
+      );
+      expect(receivedEvent.repeat, false);
+
+      RawKeyboard.instance.keyEventHandler = null;
+    }, skip: isBrowser); // [intended] This is a Windows-specific test.
+
     testWidgets('sided modifiers without a side set return all sides on Windows', (WidgetTester tester) async {
       expect(RawKeyboard.instance.keysPressed, isEmpty);
       // Generate the data for a regular key down event.
diff --git a/packages/flutter/test/widgets/shortcuts_test.dart b/packages/flutter/test/widgets/shortcuts_test.dart
index 01ef201..39f5090 100644
--- a/packages/flutter/test/widgets/shortcuts_test.dart
+++ b/packages/flutter/test/widgets/shortcuts_test.dart
@@ -464,6 +464,33 @@
       expect(RawKeyboard.instance.keysPressed, isEmpty);
     }, variant: KeySimulatorTransitModeVariant.all());
 
+    testWidgets('rejects repeated events if requested', (WidgetTester tester) async {
+      int invoked = 0;
+      await tester.pumpWidget(activatorTester(
+        const SingleActivator(
+          LogicalKeyboardKey.keyC,
+          control: true,
+          includeRepeats: false,
+        ),
+        (Intent intent) { invoked += 1; },
+      ));
+      await tester.pump();
+
+      // LCtrl -> KeyC: Accept
+      await tester.sendKeyDownEvent(LogicalKeyboardKey.controlLeft);
+      expect(invoked, 0);
+      await tester.sendKeyDownEvent(LogicalKeyboardKey.keyC);
+      expect(invoked, 1);
+      await tester.sendKeyRepeatEvent(LogicalKeyboardKey.keyC);
+      expect(invoked, 1);
+      await tester.sendKeyUpEvent(LogicalKeyboardKey.keyC);
+      await tester.sendKeyUpEvent(LogicalKeyboardKey.controlLeft);
+      expect(invoked, 1);
+      invoked = 0;
+
+      expect(RawKeyboard.instance.keysPressed, isEmpty);
+    }, variant: KeySimulatorTransitModeVariant.all());
+
     testWidgets('handles Shift-Ctrl-C', (WidgetTester tester) async {
       int invoked = 0;
       await tester.pumpWidget(activatorTester(
@@ -514,8 +541,8 @@
       expect(RawKeyboard.instance.keysPressed, isEmpty);
     });
 
-    test('diagnostics.', () {
-      {
+    group('diagnostics.', () {
+      test('single key', () {
         final DiagnosticPropertiesBuilder builder = DiagnosticPropertiesBuilder();
 
         const SingleActivator(
@@ -528,9 +555,26 @@
 
         expect(description.length, equals(1));
         expect(description[0], equals('keys: Key A'));
-      }
+      });
 
-      {
+      test('no repeats', () {
+        final DiagnosticPropertiesBuilder builder = DiagnosticPropertiesBuilder();
+
+        const SingleActivator(
+          LogicalKeyboardKey.keyA,
+          includeRepeats: false,
+        ).debugFillProperties(builder);
+
+        final List<String> description = builder.properties.where((DiagnosticsNode node) {
+          return !node.isFiltered(DiagnosticLevel.info);
+        }).map((DiagnosticsNode node) => node.toString()).toList();
+
+        expect(description.length, equals(2));
+        expect(description[0], equals('keys: Key A'));
+        expect(description[1], equals('excluding repeats'));
+      });
+
+      test('combination', () {
         final DiagnosticPropertiesBuilder builder = DiagnosticPropertiesBuilder();
 
         const SingleActivator(
@@ -547,7 +591,7 @@
 
         expect(description.length, equals(1));
         expect(description[0], equals('keys: Control + Alt + Meta + Shift + Key A'));
-      }
+      });
     });
   });
 
diff --git a/packages/flutter_tools/lib/src/linux/build_linux.dart b/packages/flutter_tools/lib/src/linux/build_linux.dart
index 49f14a1..81c86d5 100644
--- a/packages/flutter_tools/lib/src/linux/build_linux.dart
+++ b/packages/flutter_tools/lib/src/linux/build_linux.dart
@@ -38,7 +38,7 @@
   target ??= 'lib/main.dart';
   if (!linuxProject.cmakeFile.existsSync()) {
     throwToolExit('No Linux desktop project configured. See '
-      'https://flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
+      'https://docs.flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
       'to learn about adding Linux support to a project.');
   }
 
diff --git a/packages/flutter_tools/lib/src/macos/build_macos.dart b/packages/flutter_tools/lib/src/macos/build_macos.dart
index 335f634..c217750 100644
--- a/packages/flutter_tools/lib/src/macos/build_macos.dart
+++ b/packages/flutter_tools/lib/src/macos/build_macos.dart
@@ -31,7 +31,7 @@
 }) async {
   if (!flutterProject.macos.xcodeWorkspace.existsSync()) {
     throwToolExit('No macOS desktop project configured. '
-      'See https://flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
+      'See https://docs.flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
       'to learn about adding macOS support to a project.');
   }
 
diff --git a/packages/flutter_tools/lib/src/windows/build_windows.dart b/packages/flutter_tools/lib/src/windows/build_windows.dart
index 1d7a269..6422d39 100644
--- a/packages/flutter_tools/lib/src/windows/build_windows.dart
+++ b/packages/flutter_tools/lib/src/windows/build_windows.dart
@@ -32,7 +32,7 @@
   if (!windowsProject.cmakeFile.existsSync()) {
     throwToolExit(
       'No Windows desktop project configured. See '
-      'https://flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
+      'https://docs.flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
       'to learn about adding Windows support to a project.');
   }
 
@@ -124,7 +124,7 @@
   if (!windowsProject.existsSync()) {
     throwToolExit(
       'No Windows UWP desktop project configured. See '
-      'https://flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
+      'https://docs.flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
       'to learn about adding Windows support to a project.',
     );
   }
diff --git a/packages/flutter_tools/test/commands.shard/hermetic/build_linux_test.dart b/packages/flutter_tools/test/commands.shard/hermetic/build_linux_test.dart
index 9714f74..0d73157 100644
--- a/packages/flutter_tools/test/commands.shard/hermetic/build_linux_test.dart
+++ b/packages/flutter_tools/test/commands.shard/hermetic/build_linux_test.dart
@@ -114,7 +114,7 @@
     expect(createTestCommandRunner(command).run(
       const <String>['build', 'linux', '--no-pub']
     ), throwsToolExit(message: 'No Linux desktop project configured. See '
-      'https://flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
+      'https://docs.flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
       'to learn about adding Linux support to a project.'));
   }, overrides: <Type, Generator>{
     Platform: () => linuxPlatform,
diff --git a/packages/flutter_tools/test/commands.shard/hermetic/build_macos_test.dart b/packages/flutter_tools/test/commands.shard/hermetic/build_macos_test.dart
index febf951..4e5cc45 100644
--- a/packages/flutter_tools/test/commands.shard/hermetic/build_macos_test.dart
+++ b/packages/flutter_tools/test/commands.shard/hermetic/build_macos_test.dart
@@ -131,7 +131,7 @@
     expect(createTestCommandRunner(command).run(
       const <String>['build', 'macos', '--no-pub']
     ), throwsToolExit(message: 'No macOS desktop project configured. See '
-      'https://flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
+      'https://docs.flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
       'to learn about adding macOS support to a project.'));
   }, overrides: <Type, Generator>{
     Platform: () => macosPlatform,
diff --git a/packages/flutter_tools/test/commands.shard/hermetic/build_windows_test.dart b/packages/flutter_tools/test/commands.shard/hermetic/build_windows_test.dart
index 1244d02..a85bec4 100644
--- a/packages/flutter_tools/test/commands.shard/hermetic/build_windows_test.dart
+++ b/packages/flutter_tools/test/commands.shard/hermetic/build_windows_test.dart
@@ -159,7 +159,7 @@
     expect(createTestCommandRunner(command).run(
       const <String>['windows', '--no-pub']
     ), throwsToolExit(message: 'No Windows desktop project configured. See '
-      'https://flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
+      'https://docs.flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
       'to learn about adding Windows support to a project.'));
   }, overrides: <Type, Generator>{
     Platform: () => windowsPlatform,
@@ -489,7 +489,7 @@
     expect(createTestCommandRunner(command).run(
       const <String>['winuwp', '--no-pub']
     ), throwsToolExit(message: 'No Windows UWP desktop project configured. See '
-      'https://flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
+      'https://docs.flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
       'to learn about adding Windows support to a project.'));
   }, overrides: <Type, Generator>{
     Platform: () => windowsPlatform,