Documentation licence not compatible with Free Software
The current user documentation is licensed under the CC BY-NC-SA 3.0 licence which means the documentation isn't compatible with free software. This effectively prevents distributions or other software compilations from including the documentation for darktable in the distribution or repositories since they allow the distribution to be used for commercial purposes.For more information (and a generally interesting read) I found this artical at freedom defined particularly useful.
Basic rule of thumb when using a CC licence for free software goes :
#4 Updated by Tobias Ellinghaus over 7 years ago
Since Olivier Tribout agreed to dropping the NC in this mail http://sourceforge.net/mailarchive/message.php?msg_id=27892662 and Jo and me didn't have a problem with that either I hereby declare that it shall be done. :)