Best I could find about data file status is in this thread http://tyrian2k.proboards.com/index....ead=103&page=1 and in this blog post http://lostgarden.com/2007/04/free-g...ships-and.html .

How I see things is that there isn't any explicit license (other than freeware). People in the thread don't think that data files are freely (as in debian free) redistributable except for the graphics files.