It's under CC-BY-SA, which is very incompatible with pretty much everything else.

That’s funny, I guess everyone just ignores that, but legally it means AI should not be trained on it either since it requires attribution, I wonder was it always that way?

I think AI companies are just trying to ignore IP laws entirely, perhaps they’ll get away with it but there is bound to be a case where a small tool or game is 90% identical to a source reference at some point given the way these LLMs work.