All over tbh, most devs are using it to some degree now.
However it's not an "AI" FOSS contribution, it'll be Doug contributing, or Pardep, or whatever.
They just quietly used AI like a normal person for some basic parts of the code to get it done faster, then tweaked it to look better.
I'd expect most FOSS projects with contributions in the past 6months have bits and pieces, a line here or there, written in AI
That's the thing, when the AI performs well, you wouldn't even be able to tell AI was used