[This article was contributed by Joe 'Zonker' Brockmeier]
The GNU Free
Documentation License (GFDL) may not be suitable if you're hoping to
have your documentation included in Debian "main."
The nature of the problem is described in this
proposed statement written by Anthony Towns. If adopted as an
"official" statement from the Debian project, GFDL-licensed documents will
find themselves excluded from the free portion of the Debian distribution.
The conflict between the GFDL and the Debian Free Software
Guidelines (DFSG) comes in when the author includes "Invariant"
sections or an Acknowledgements or Dedications section. These are described
in section 4 of the GFDL. Essentially, the GFDL requires that these
sections not be modified or removed, which goes against the (DFSG)
requirement that a license "must allow modifications and derived works."
One may avoid the conflict by simply not including the sections that are
troublesome, or by using another license. However, that may not satisfy some
authors and definitely doesn't solve the problem for documents already
For many documents, this may not be a problem. If an author insists on
using the GFDL and one of the troublesome sections, users can simply
grab the documentation elsewhere or even as a Debian package just by
getting the package from the "non-free" collection of Debian packages.
However, when another program includes the documentation, it may make
things a bit trickier. According to Richard Braakman the GFDL puts a "wall between documentation and code."
The GFDL is incompatible with the GPL, and many of its requirements
don't translate well to functional software. This makes it difficult to
embed such documents into a program, for example in order to present
on-line help. In the other direction, many documents contain example
code, sometimes sizeable chunks of it, which will be unusable by default
unless specifically licensed otherwise.
Braakman also raises a few other issues that he considers problematic
with the GFDL. One that is interesting to note is the idea that
"languages other than English are poorly supported."
The GNU FDL defines special roles for several kinds of sections (such as
"History" and "Dedications"), but refers to these sections by their
names in English. A document under the GNU FDL will have to include a
section with the title "History", regardless of the language it's
One could ask whether the Debian project should make an exception for
documentation. The rules that apply to code may not work so well for
documentation, particularly when good documentation is even harder to
come by than good code. The Debian developers are not known for
compromising on their principles, however. It will be interesting to see
what the final
outcome of this discussion will be, but it looks entirely likely that
the Debian project may decide that one of the GNU Free licenses is, in
fact, not free enough.
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