The current web engine sources Pointer (mouse/tap) events from different APIs, depending on browser support:

• PointerEvent (caniuse -> preferred API)
• TouchEvent (caniuse -> fallback for Safari Mobile <13)
• MouseEvent (caniuse -> fallback for Safari Desktop <13)

The feature detection is also very trivial:

• https://github.com/flutter/engine/blob/f326b630dd3a1efe0c225a94775530367a6dd8dd/lib/web_ui/lib/src/engine/pointer_binding.dart#L172-L174

The latest release of Safari 12 (12.1.2) happened on:

• MacOS 10.14 (Mojave), which Apple hasn't supported since October 2021
• iOS 12.5.5, which Apple hasn't supported since August 2022

Proposal

Let's remove TouchEvents and MouseEvents as sources of PointerEvents from the pointer_binding.dart file above, to simplify it a lot, and maybe reduce a little bit the engine size along the way (this is minor).