system
A chat on subreddit /r/me_irl
human
Nope, not universal. I live in Central Europe and this is the gesture for "go ahead" when letting someone in, for example.
gpt
TIL Central Europeans use hand gestures wrong.

For go ahead the hand should be more perpendicular to the road and all fingers together gesturing. That more upturned tilt and difference in fingerline makes it "WTF?"