> That only matters if expression of the original project really does end up in the rewrite, doesn't it?

No, I don't think so. I hate comparing LLMs with humans, but for a human being familiar with the original code might disqualify them from writing a differently-licensed version.

Anyway, LLMs are not human, so as many courts confirmed, their output is not copyrightable at all, under any license.

Uh, this is just a curiosity, but do you have a reference for that last argument?

If true, it would mean most commercial code being developed today, since it's increasingly AI-generated, would actually be copyright-free. I don't think most Western courts would uphold that position.