>The way the proposers portray it, this problem is a dealbreaker. Is the problem as portrayed? Do LLM vendors attempt to copyright the output?
They're right that this has not been fully tested in court (though neither have some other open source licenses). There's a pretty clear direction that the wind is blowing in, though (you can see in most related cases that the judges focus on issues surrounding the core idea of using copyrighted data for training, and mostly don't give credit to the idea that all of a model's output is a derivative work of all of the input). I don't believe any LLM vendors try to claim copyright on the output of the models.
>How can a contributer know if LLM output includes "pre-existing copyrighted materials (including pre-existing code licensed as free software) authored or owned by third parties"? They can't be familiar with all pre-existing code in the world.
This is a common objection/worry. It seems relatively clear that even if most of the output of an LLM is not subject to existing copyright, some of it could well be (especially if, e.g. you feed an LLM a codebase and ask it to just output it again verbatim or with different variable and function names). What exactly the risks are if you are if this happens while you are using the LLM in good faith is pretty unclear (the vendors pretty much just say "It's at your own risk").
(This case felt a little surprising to me, BTW: https://petapixel.com/2026/07/22/dog-photographer-loses-copy... . But copyright case law is weird, arbitrary, and somewhat capricious about what aspects of a work are and aren't protected by copyright. With code this can also potentially be weird because in principle the functional parts are not protected, only the human expression components are. Untangling this can be time consuming, expensive, and ugly)