An anecdote that goes against the conventional wisdom about IMEs vs. ”English” and emoji: Right now in Firefox and Chrome, the events that get fired are more correct if you enter emoji using the Windows 10 Pinyin IME’s emoji palette than if you enter emoji using the Windows 10 on-screen English keyboard’s emoji palette.

Edited to elaborate: Keyboard APIs aren't well exercised for astral characters, but IME APIs deal with strings anyway.