As of version 1.65 of man-pages, the upstream project this package is
based on, manual pages from the POSIX standard are included.  The
man-pages project is permitted to distribute them and Andries Brouwer
assumes that re-distribution by vendors is permitted as well.

However, modification is definitively not allowed, hence this great
contribution by The Institute of Electrical and Electronics Engineers
and The Open Group (see <http://linuxpr.com/releases/6599.html>)
render the entire man-pages package non-free.

It would have been a better idea to distribute POSIX manpages in a
separate file if at all, so that free and non-free components aren't
mixed and non-free components don't get a chance to contaminate the
free manpages packages.

Hence, the file manpages*.orig.tar.gz is no longer exactly the
pristine upstream source tarball as one would expect, since that would
render that all manpages resulting manpages packages non-free.
Instead it is the upstream file with the file POSIX-COPYRIGHT and the
directories man0p, man1p and man3p removed, so that only the usual
free components are included.

Francesco Paolo Lovergine <frankie@debian.org> has packaged the
non-free POSIX manpages as manpages-posix which are distributed by the
Debian project in the non-free archive.
