anchor.diff:    /// Use `createSyntheticMouseEvent` instead.
     external factory SyntheticMouseEvent._();
   
  -  /// Returns true if the `alt` key was down when the mouse event was fired.
  +  /// Whether the `alt` key was down when this event was fired.
     ///
     /// See <https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent/altKey>
     external bool get altKey;
   
  -  /// The button number that was pressed (if applicable) when the mouse event was fired.
  +  /// The button number that was pressed (if applicable) when this event was fired.
     ///
     /// See <https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent/button>
     external num get button;
   
  -  /// The buttons being depressed (if any) when the mouse event was fired.
  +  /// The buttons being depressed (if any) when this event was fired.
     ///
     /// See <https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent/buttons>
     external num get buttons;
  
positive.code:   /// See <https://developer.mozilla.org/en-US/docs/Web/API/AnimationEvent/elapsedTime>
    external num get elapsedTime;
  
    /// Is a DOMString, starting with '::', containing the name of the pseudo-element the animation runs on.
    ///
    /// If the animation doesn't run on a pseudo-element but on the element, an empty string: ''.
    ///
  
negative.code:   /// See <https://developer.mozilla.org/en-US/docs/Web/API/PointerEvent/twist>
    external num get twist;
  
    /// Indicates the device type that caused this event (mouse, pen, touch, etc.)
    ///
    /// See <https://developer.mozilla.org/en-US/docs/Web/API/PointerEvent/pointerType>
    external String get pointerType;
  