What it's trained on shouldn't matter at all. What should matter is what it's capable of outputting, and whether that covers works in which someone holds copyri

What it's trained on shouldn't matter at all. What should matter is what it's capable of outputting, and whether that covers works in which someone holds copyright - so something regurgitating its input would be problematic, but something not capable of producing the same format of output as its input should be in the clear. Otherwise you're talking about something that shouldn't come under copyright law.