I don't think it's that clear cut. The functional parts probably aren't copyrightable, only the stylistic ones. It's going to be a mix of courts applying laws in new ways that hasn't been done before and fact specific questions about what actually persisted through the LLM if it goes to court.

I'd be fascinated to see what happens if it does. Both in the analyses that we'd get of what the LLM did to the codebase and on the legal decisions on what the copyrightable creative elements in code actually are.

If I was the author though... there would be no way that I would be volunteering to be a test case like this. Also seems just rude for no reason.

I suspect that the issue is more likely that the LLM code doesn't have an author and hence some parts of it can't be licenses, it's less likely that it's infringing on git's copyright for various reasons. (I am not a lawyer, but I do read copyright law for funsies).