Well I shouldn't have to publish them, if I'm not distributing that software. Your private forks are private, even if you produce something using them. You can

Well I shouldn't have to publish them, if I'm not distributing that software. Your private forks are private, even if you produce something using them. You can't taint that production or force someone to publish changes they don't want to publish and aren't distributing. You are saying if a textbook publisher modifies open source layout software then uses it to set a textbook, they can't retain those internal modifications if someone asks to see them. I think they should be able to keep them private.