I'm not a lawyer as well, but I think Roberts statements are true.
> > I do not, however, see any explicit note in the PDF file that says
> > that the
> > _documentation_ is released under the GPL (only with regards to the
> > source).
I don't think that this distiction between source and documentation is
meaningful in this case. Clearly the texinfo files are the source of
the generated pdf. Also the texinfo files are tightly integrated with
the actual maxima program via the describe system.
> > Also since Maxima/Macsyma has been released under several
> > licenses in the past, including non-free ones, I believe that it is
> > possible (though unlikely?) that this document is not GPL'd even if
> > previous manuals were.
I don't think that anything from before the fork from doe macsyma is
relevant. Do you know any part of maxima that was added after the
fork but is not licensed under free (and GPL compatible) terms?
Since some parts of the document obviously are GPL'd, it is not
possible that the document as a whole is not GPL'd (or GPL compatible)
without making the document (legally) undistributable at all.
> > The license and `freeness' of the documentation would be a good thing to
> > clear up.
I wouldn't waste any effort on this. Should there ever arise any problems,
we need to rewrite the relevant parts anyway. And following the above
explanation we are definitely acting in good faith.
> Documentation should be released under the FDL (not GPL).
No, the FDL is not a free license. For example Debian wouldn't
distribute the maxima manual anymore. And even worse:
> There may be some legal issues with moving to FDL.
Indeed, the FDL is incompatible with the GPL. Thus to move the license
to GPL we would need to get consent from all current copyright holders
(all past contributors or their heirs). That would be an insane waste
of effort and time.
HTH
Harald