Both Mouse Events and Wheel Events are currently defined in the UI Events spec. During TPAC 2024, we agreed to migrate MouseEvent definitions from there to the Pointer Events spec (see WebAppsWG Day 3 notes on "topic: ui events").

Should we do the same with WheelEvent definitions?

One possible first step seems to be making WheelEvent a subclass of PointerEvent, from being a subclass of MouseEvent. Could this be a compat concern?