anchor.diff:    /// Use `createSyntheticClipboardEvent` instead.
     external factory SyntheticClipboardEvent._();
   
  +  /// Holds a [DataTransfer] object, which can be used:
  +  ///
  +  /// - to specify what data should be put into the clipboard from the cut and copy event handlers, typically with a
  +  /// setData(format, data) call;
  +  /// - to obtain the data to be pasted from the paste event handler, typically with a getData(format) call.
  +  ///
  +  /// See: <https://developer.mozilla.org/en-US/docs/Web/API/ClipboardEvent/clipboardData>
     external get clipboardData;
   }
   
  +/// A [SyntheticEvent] wrapper that is specifically backed by a [KeyboardEvent].
  +///
  +/// See <https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent>
   @JS()
   class SyntheticKeyboardEvent extends SyntheticEvent {
     /// [SyntheticKeyboardEvent]s cannot be manually instantiated.
  
positive.code:   /// Use `createSyntheticFocusEvent` instead.
    external factory SyntheticFocusEvent._();
  
    external EventTarget get relatedTarget;
  }
  
  @JS()
  class SyntheticFormEvent extends SyntheticEvent {
    /// [SyntheticFormEvent]s cannot be manually instantiated.
  
negative.code:   /// Use `createSyntheticTouchEvent` instead.
    external factory SyntheticTouchEvent._();
  
    /// A value indicating whether or not the alt key was down when the touch event was fired.
    ///
    /// See <https://developer.mozilla.org/en-US/docs/Web/API/TouchEvent/altKey>
    external bool get altKey;
  
    /// All the `Touch` objects representing individual points of contact whose states changed between the
    /// previous touch event and this one.
    ///
    /// See <https://developer.mozilla.org/en-US/docs/Web/API/TouchEvent/changedTouches>
    external TouchList get changedTouches;
  
    /// A value indicating whether or not the control key was down when the touch event was fired.
    ///
    /// See <https://developer.mozilla.org/en-US/docs/Web/API/TouchEvent/ctrlKey>
    external bool get ctrlKey;
  
    /// A value indicating whether or not the meta key was down when the touch event was fired.
    ///
    /// See <https://developer.mozilla.org/en-US/docs/Web/API/TouchEvent/metaKey>
    external bool get metaKey;
  
    /// A value indicating whether or not the shift key was down when the touch event was fired.
    ///
    /// See <https://developer.mozilla.org/en-US/docs/Web/API/TouchEvent/shiftKey>
    external bool get shiftKey;
  
    /// All the `Touch` objects that are both currently in contact with the touch surface and were also
    /// started on the same element that is the target of the event.
    ///
    /// See <https://developer.mozilla.org/en-US/docs/Web/API/TouchEvent/targetTouches>
    external TouchList get targetTouches;
  
    /// All the `Touch` objects representing all current points of contact with the surface, regardless
    /// of target or changed status.
    ///
    /// See <https://developer.mozilla.org/en-US/docs/Web/API/TouchEvent/touches>
    external TouchList get touches;
  }
  
  /// A [SyntheticEvent] wrapper that is specifically backed by a [TransitionEvent].
  ///
  /// See <https://developer.mozilla.org/en-US/docs/Web/API/TransitionEvent>
  @JS()
  class SyntheticTransitionEvent extends SyntheticEvent {
    /// [SyntheticTransitionEvent]s cannot be manually instantiated.
  