The U.S. Supreme Court just declined to hear a case, thus upholding a lower court precedent that LLM output are not copyrightable: https://www.reuters.com/legal/government/us-supreme-court-de...

What this means in practice is that (currently), all output of an LLM is legally considered to not be copyrightable (to the extent that it's an original work). If it happens to regurgitate an existing copyrighted work, though, is that infringement? I'm not sure we have a legal precedent on that question yet.