The GlobalEventHandlers mixin describes the event handlers common to several interfaces like HTMLElement, Document, or Window. Each of these interfaces can implement more event handlers.
The ImageBitmapFactories mixin interface contains utility methods to create an ImageBitmap. There is no object of this type, but the two interfaces Window, available within the regular browsing scope, and the WorkerGlobalScope interface for workers, implement this interface.
WindowTimers is a mixin used to provide utility methods which set and clear timers. No objects of this type exist; instead, its methods are available on Window for the standard browsing scope, or on WorkerGlobalScope for workers.