The Free Software Foundation (FSF) clarifies
the purpose of its copyright policies and examines the impact of
potential alternatives.
For some GNU packages, the ones that are FSF-copyrighted, we ask contributors for two kinds of legal papers: copyright assignments, and employer copyright disclaimers. We drew up these policies working with lawyers in the 1980s, and they make possible our steady and continuing enforcement of the GNU General Public License (GPL).
These papers serve four different but related legal purposes, all of which help ensure that the GNU Project’s goals of freedom for the community are met.