invariant section

Controversial borderline cases

Also, the FSF recommended GNU Free Documentation License, which is incompatible with the GPL, was considered "non-free" by the Debian project around 2006, Nathanael Nerode, and Bruce Perens. The FSF argues that documentation is qualitatively different from software and is subject to different requirements. Debian accepted, in a later resolution, that the GNU FDL complied with the Debian Free Software Guidelines when the controversial "invariant section" is removed, but considers it "still not free of trouble". Notwithstanding, most GNU documentation includes "invariant sections". Similarly, the FLOSS Manuals foundation, an organization devoted to creating manuals for free software, decided to eschew the GFDL in favor of the GPL for its texts in 2007, citing the incompatibility between the two, difficulties in implementing the GFDL, and the fact that the GFDL "does not allow for easy duplication and modification", especially for digital documentation.