Interesting. In addition to Anthropic's watermark use to prevent model collapse, we can definitively call something copyrighted or not copyrighted. This is a boon to everyone who consumes culture.
However! Since AI work is noncopyrightable, the AI’s effort in translation is simply ignored. Claude’s The Odyssey would have zero rightsholders, and remain public domain. ChatGPT’s translation of The Three Body Problem would still be under Liu Cixin’s copyright.