There’s a discussion about using ? instead of the is / has prefix convention here: Question mark in variable names
I’m not a fan, and I am even more critical about using a unicode-questionmark thing. I think unicode is great in variable names (makes source code much nicer and more readable), but not in function or type names, and certainly not in exported names.
Isn’t that pretty much established practice? Allow unicode, but don’t force it on users?