Anthony Towns | 1 Jan 2006 06:02

GR Proposal: GFDL statement

Bcc'ed to -project, -legal and -private; followups to -vote please.

It's been six months since the social contract changes that forbid
non-free documentation went into effect [0], and we're still distributing
GFDLed stuff in unstable [1]. I think we should get serious about fixing
that, and as part of that that we should release the following statement
(or one like it) on the GFDL:

Why the GNU Free Documentation License is not suitable for Debian main

(0) Summary

Within the Debian community there has been a significant amount of concern
about the GNU Free Documentation License (GFDL), and whether it is, in
fact, a "free" license. This document attempts to explain why Debian's
answer is "no".

It should be noted that this does not imply any hostility towards the
Free Software Foundation, and does not mean that GFDL documentation
should not be considered "free enough" by others, and Debian itself will
continue distributing GFDL documentation in its "non-free" section.

(1) What is the GFDL?

The GFDL is a license written by the Free Software Foundation, who use
it as a license for their own documentation, and promote it to others. It
is also used as Wikipedia's license. To quote the GFDL's Preamble:

  freedom: to assure everyone the effective freedom to copy and
  redistribute it, with or without modifying it, either commercially or
  noncommercially. Secondarily, this License preserves for the author
  considered responsible for modifications made by others.

  complements the GNU General Public License, which is a copyleft license
  designed for free software.

(2) How does it fail to meet Debian's standards for Free Software?

The GFDL conflicts with traditional requirements for free software in
a variety of ways, some of which are expanded upon below. As a copyleft
license, one of the consequences of this is that it is not possible to
include content from a documention directly into free software under
the GFDL.

The major conflicts are:

(2.1) Invariant Sections

The most troublesome conflict concerns the class of invariant sections
that, once included, may not be modified or removed from the documentation
in future. Modifiability is, however, a fundamental requirement of the
DFSG, which states:

    3. Derived Works
    The license must allow modifications and derived works, and
    must allow them to be distributed under the same terms as the
    license of the original software.

Invariant sections create particular problems in reusing small portions
of the work (since any invariant sections must be included also,
however large), and in making sure the documentation remains accurate
and relevant.

(2.2) Transparent Copies

The second conflict is related to the GFDL's requirements for "transparent
copies" of documentation (that is, a copy of the documentation in a form
suitable for editing). In particular, Section 3 of the GFDL requires
that a transparent copy of the documentation be included with every
opaque copy distributed, or that a transparent copy is made available
for a year after the opaque copies are no longer being distributed.

For free software works, Debian expects that simply providing the source
(or transparent copy) alongside derivative works will be sufficient,
but this does not satisfy either clause of the GFDL's requirements.

(2.3) Digital Rights Management

The third conflict with the GFDL arises from the measures in Section 2
that attempt to overcome Digital Rights Management (DRM) technologies. In
particular, the GFDL states that "You may not use technical measures
make or distribute". This inhibits freedom in three ways: it limits use
of the documentation as well as distribution, by covering all copies
made, as well as copies distributed; it rules out distributing copies
on DRM-protected media, even if done in such a way as to give users
full access to a transparent copy of the work; and, as written, it also
potentially disallows encrypting the documentation, or even storing it
on a filesystem that supports permissions.

(3) Why does documentation need to be Free Software?

There are a number of obvious differences between programs and
documentation that often inspire people to ask "why not simply have
different standards for the two?" For example, books are often written
by individuals, while programs are written by teams, so proper credit
for a book might be more important than proper credit for a program.

On the other hand, free software is often written by a single person,
and free software documentation is often written by a larger group of
contributors.  And the line between what is documentation and what is
a program is not always so clear either, as content from one is often
needed in the other (to provide online help, to provide screenshots or
interactive tutorials, to provide a more detailed explanation by quoting
some of the source code). Similarly, while not all programs demonstrate
creativity or could be considered "works of art", some can, and trying
to determine which is the case for all the software in Debian would be
a distraction from our goals.

In practice, then, documentation simply isn't different enough to warrant
different standards: we still wish to provide source code in the same
manner as for programs, we still wish to be able to modify and reuse
documentation in other documentation and programs as conveniently as
possible, and we wish to be able to provide our users with exactly the
documentation they want, without extraneous materials.

(4) How can this be fixed?

What, then, can documentation authors and others do about this?

An easy first step is to not include the optional invariant sections in
your documentation, since they are not required by the license, but are
simply an option open to authors.

Unfortunately this alone is not enough, as other clauses of the GFDL
render all GFDL documentation non-free. As a consequence, other licenses
should be investigated; generally it is probably simplest to choose
either the GNU General Public License (for a copyleft license) or the
BSD or MIT licenses (for a non-copyleft license).

As most GFDL documentation is made available under "the terms of the GNU
Free Documentation License, Version 1.2 or any later version published
by the Free Software Foundation", the Free Software Foundation is able
to remedy these problems by changing the license. The problems discussed
above require relatively minor changes to the GFDL -- allowing invariant
sections to be removed, allowing transparent copies to be made available
concurrently, and moderating the restrictions on technical measures.
Unfortunately, while members of the Debian Project have been in
contact with the FSF about these concerns for the past four years,
these negotiations have not come to any conclusion to date.  

It's based on Manoj's draft position statement [2] with some notable
changes (an explicit "why not just say docs != software" section, a
"how can this be fixed" section, a "what is the GFDL?" section, and
reordering the major problems). I've put the above draft on the wiki
[3] so people can tweak it.


[1] <at>