GCC's manpage refers to sections that aren't in the manpage

["Jordi Gutierrez Hermoso" <jordigh@gmail.com>]

I'm rather confused. The GCC maintainers put the manpage in non-free
along with the rest of the GCC docs. The manpage says at the bottom
that it's covered by the GFDL and mentions invariant sections that
aren't in the manpage. Huh? What does this mean as far as the location
of the manpage and the GFDL/Debian fiasco?

Slightly annoyed,
- Jordi G. H.