I think that the GPL uses the term "derivative work" which is quite vague when it is not applied to code. Many software distributions encourage their upstream t

I think that the GPL uses the term "derivative work" which is quite vague when it is not applied to code. Many software distributions encourage their upstream to use specific licenses such as one of the Creative Common licenses to cover art. That's true for text too ; for example most pages on gnu.org are licensed under CC-BY-ND. Unfortunately, as the -NC and -ND licenses add restrictions, some distributions such as Debian don't consider it free software (cf. [DFSG]). [DFSG]: http://www.debian.org/social_contract http://www.debian.org/social_contract