There's been no significant litigation to establish case law on FOSS licensing. That's always bugged me, but I get it -- we behave as if the licenses are valid (and, yeah, I think so?), and folks who consume the code have mostly caved when threatened with lawsuits.
But now it gets interesting. Models trained on FOSS will do clean-room implementations of GPL code to get rid of virality:
https://www.youtube.com/watch?v=6godSEVvcmU
I'm out of the racket, but somebody oughtta take this one to court.
