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REVISED PROPOSAL regarding DFSG 3 and 4, licenses, and modifiable text

[Debian Policy group: I am not sure if the Debian Policy Manual is an
appropriate forum for any of the following material.  I invite your

[Debian GNU Emacsen maintainers: I'd appreciate your assistance in some
fact-finding; see particularly the end of this mail.]


Per recent discussion on the debian-legal mailing list regarding DFSG
section 3 and provisions of recent documentation-specific licenses that
have been developed in recent years, that allow for non-modifiable
portions of the work (such as the license text itself) and mandate the
display of certain text on the outside surfaces of physical media, I am
proposing a guideline for interpretation of the DFSG that clarifies the
criteria that a license must meet to satisfy the DFSG.


The following clauses of the Debian Free Software Guidelines should be
held in mind when reading my proposal.  Keep in mind that my proposed
guidelines are only that; any generally perceived conflict between the
DFSG and my guidelines must be resolved in favor of the DFSG until and
unless the DFSG is amended.  These guidelines are proposed and intended
as a "gentlemens' agreement" to clarify certain areas rendered ambiguous
by the DFSG or by current practice in the Debian Project.  (If any
portion of this proposal is regarded as suitable for inclusion in the
Debian Policy Manual, those portions will, of course, have slightly more
force upon Debian Developers than a "gentlemens' agreement".)

DFSG Clause 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.

DFSG Clause 4: Integrity of The Author's Source Code

The license may restrict source-code from being distributed in modified
form _only_ if the license allows the distribution of "patch files" with
the source code for the purpose of modifying the program at build time.
The license must explicitly permit distribution of software built from
modified source code. The license may require derived works to carry a
different name or version number from the original software. (This is a
compromise. The Debian group encourages all authors not to restrict any
files, source or binary, from being modified.)

For further reading:

The Debian Free Software Guidelines ("DFSG") and Social Contract:

The GNU General Public License ("GNU GPL"):

The GNU Free Documentation License ("GNU FDL"):

The Open Publication License ("OPL"):

Previous debian-legal discussion:
...and most of the subsequent traffic for the month, spilling over into

There are several aspects to my proposal.  Each is followed by some
explanatory text.


1) Copyright notices used as such (i.e., not as examples) are permitted
to be held non-modifiable.
	Note that a copyright notice is not the same thing as a license
	text.  A copyright notice is simply an assertion of copyright,
	such as "Copyright (C) 1900 American Widget Corporation".  This
	proposal is made because modification of copyright notices is
	construed as infringement of copyright in many jurisdictions in
	the world.

	This guideline is proposed to legitimize the status quo within

2) License text used as such (i.e., not as an example), and applied by
one or more copyright holders to a work submitted for distribution by
the Debian Project, is permitted to be held non-modifiable.  The
licensee must have discretion to include or exclude the text of the
license in alternative formats and/or locations outside the package's
copyright file.
	License terms typically comprise the bulk of a debian/copyright
	file; examples of common license terms may be found in
	/usr/share/common-licenses on Debian systems.  Note that the
	placement of a license in /usr/share/common-licenses is a means
	of economizing on package size (both in packaged and installed
	forms); their intended purpose is as such, since Debian Policy
	instructs Debian package maintainers to not include the texts of
	these common licenses in their own packages' copyright files.

	Only actual contractual license terms are protected under this
	interpretive clause.  Material that is used to inform, persuade,
	exhort, or otherwise interact with the (putative) licensee but
	which is not legally binding is not covered by this clause.

	The last sentence is merely a fancy way of saying that stating
	the license terms once within a package (at least in its
	installed form on a Debian system) must be sufficient to satisfy
	the license.  A license must not require, but may permit, that
	its text be duplicated in other formats (such as HTML) or
	locations (such an "info" document) in a work.

	This guideline is proposed to legitimize the status quo within

3) An amount of non-modifiable auxiliary material which is not legally
binding upon a licensee is permitted to exist in conjunction with the
license terms, and the packaging of the work so licensed should reflect
this.  Such material may not exceed 32 binary kilobytes (32,768 bytes)
when viewed in plain-text form (treating all adjacent white space
characters as one byte), and must be included in the debian/copyright
file.  Non-textual, binary data held as non-modifiable information by
the copyright holder(s) also counts byte-for-byte toward this limit.
The location of any such non-textual, non-modifiable information must be
referenced from the debian/copyright file.  The licensee must have
discretion to include or exclude this non-license, non-modifiable
auxiliary material in alternative formats and/or locations within the
	The size of the GNU GPL and the "Funding Free Software" portion
	of the gcc manual together in plain-text form is 20,410 bytes.
	This is *without* regarding all adjacent white space characters
	as one byte, and without excluding the portion of the GPL that
	is actually a binding license.  Once that is done (condensing
	whitespace and omitting the "TERMS AND CONDITIONS" part of the
	GNU GPL, which are already covered by clause 2 above), this
	auxiliary material consumes only 7,928 bytes.  Therefore, 32,768
	bytes strikes me as a reasonable limit.

	The last sentence is merely a fancy way of saying that including
	the auxiliary once within a package (at least in its installed
	form on a Debian system) must be sufficient to satisfy the
	license.  A license must not require, but may permit, that such
	auxiliary material be duplicated in other formats or locations
	in a work.

	This guideline is proposed to legitimize the status quo in
	Debian (since we do have 4-clause-BSD-licensed packages in
	main), and also to be cognizant of the GNU FDL promulgated by
	the Free Software Foundation, without condoning abuse of the GNU
	FDL to burden free (thus modifiable) documentation with large
	quantities of unmodifiable text.


Impact of this proposal:

1) Works licensed under existing, understood-as-DFSG-free licenses are
not, in general, adversely impacted by this proposal.  The GNU GPL, GNU
LGPL, Artistic License, MIT/X Consortium license, and 2- and 3-clause
forms of the BSD license are unaffected.  The 4-clause form the of the
BSD License is be affected if the quantity of notices required by its
third clause exceeds 32,768 bytes.  However, I know of no
4-clause-BSD-licensed package that requires such a large volume of
advertising notices.

2) Works licensed under the OPL meet the DFSG if and only if neither of
the license options listed in section 6 of the OPL are exercised.

3) Works licensed under the GNU FDL meet the DFSG if and only if the
quantity of material identified as Invariant Sections or Cover Texts
does not exceed 32,768 bytes (see clause 3 of my proposal for details).

4) Works licensed under the traditional GNU documentation license, which

   Permission is granted to make and distribute verbatim copies of this
   manual provided the copyright notice and this permission notice are
   preserved on all copies.

   Permission is granted to copy and distribute modified versions of
   this manual under the conditions for verbatim copying, provided that
   the entire resulting derived work is distributed under the terms of a
   permission notice identical to this one.

   Permission is granted to copy and distribute translations of this
   manual into another language, under the above conditions for modified
   versions, except that this permission notice may be stated in a
   translation approved by the Free Software Foundation.

are not adversely impacted by this proposal.

5) The only package already in Debian that I know of that may be
affected by this guideline is, unfortunately, the GNU Emacs Manual.
Other GNU manuals, such as those for gawk, gcc, make, texinfo, and
glibc, are not affected as far as I have been able to determine (I own
paper copies of these manuals and did check).  Even the GNU Emacs Manual
itself may not be affected depending on the quantity of material within
it identified as Invariant.  I welcome the assistance of others in
exploring this issue further; however, the Free Software Foundation
appears to be unwilling to negotiate further on this matter (so please
don't bother them about it).

I welcome feedback on this proposal, but please read the archives of
debian-legal as referenced above before responding.  A great deal of
ground has already been covered, particularly in discussions with
Richard Stallman of the Free Software Foundation.

G. Branden Robinson                |    Damnit, we're all going to die;
Debian GNU/Linux                   |    let's die doing something *useful*!
branden@debian.org                 |    -- Hal Clement, on comments that
http://people.debian.org/~branden/ |       space exploration is dangerous

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