The Free Software Foundation (FSF) is the steward of the family of GNU
General Public Licenses (GPL), which we designed with care to ensure
that copyright holders have a tool to release programs as free
software in a way that perpetuates the freedom of computer users. The
licenses include explicit grant of rights necessary to exercise the
freedoms as defined in the Free Software Definition, clear and
comprehensive obligations to provide source code, and copyleft clauses
that ensure the freedoms are protected in derivative works. For over three
decades, the GPLs have been at the core of the free software movement.
And whenever a recipient of a GPL-licensed software sees the license,
they know they have all the essential freedoms in a clear and
unambiguous manner.
Unfortunately, some authors engage in confusing practices by drafting
licenses using existing terms and conditions of GNU free software
licenses, without the intention of granting all four freedoms to
users. For example, we have long seen attempts to add restrictions to
the license text itself, placed in the LICENSE file, or included
elsewhere in the program’s release. An example is the so-called
“Commons Clause,” which, when applied to a free software license,
affirms that the program is covered by the license. But, at the same
time, is contradicting in its meaning by asserting that selling copies
of the program or implementing a commercial service with the program
is prohibited.
The immediate consequence of the practice of inserting a restriction
into a GNU license in this way is the confusion it causes for the
community. Users still see the name of the original license, with its
preamble and terms and conditions intact, transmitting a strong
message that the purpose of the license is to enable users — grant
users — their essential software freedoms. This message is clear from
the license’s text, and is bolstered from the renown accrued by the
FSF and GNU trademarks, and their decades of free software advocacy.
At the same time, these same users see a contradictory statement of
the “Commons Clause,” which is clearly contrary to the sprit of the
free software movement and the Free Software Definition.
In the drafting process of the now current version 3 of GNU licenses,
in 2007, we were already aware of practices of misleading and
confusing licensing that were misusing the intent of the GNU GPLv2 by
adding language that prohibited certain uses.
We wanted to empower users to remove any additional restrictions that
may have been added to the license. Thus, we included this in GNU
GPLv3 and AGPLv3, Section 7, titled “Additional Terms.” It starts by
discussing additional permissions, and then it enumerates the possible
restrictions that may be added to the program after which it states
the following:
All other non-permissive additional terms are considered “further
restrictions” within the meaning of section 10. If the Program as
you received it, or any part of it, contains a notice stating that
it is governed by this License along with a term that is a further
restriction, you may remove that term.
Further explanation of this mechanism is available in the “Opinion on
Additional Terms” issued during the GNU GPLv3 drafting process:
Here we were particularly concerned to address the problem of
program authors who purport to license their works in a misleading
and possibly self-contradictory fashion, using the GPL together with
unacceptable added restrictions that would make those works non-free
software.
It is important to understand that this language in Section 7, when
the license is used on an actual piece of software, is a permission
given by the licensor to the licensee. To make it even clearer that
added restrictions are incompatible with our license, we gave users
the right to delete such added restrictions and preserve the program’s
freedom. But we at the FSF have another legal tool against attempts to
release programs under GNU General Public Licenses that have been
wrongly altered to become nonfree licenses.
The FSF holds copyrights and common law trademarks to the GNU family
of General Public Licenses. Moreover, the FSF holds registered
trademarks for “FSF,” “Free Software Foundation,” and “GNU.”
The FSF has always allowed everyone to use our licenses according to
their intended purpose, which is to grant and protect user freedoms
to run, copy, distribute, study, change, and improve the software. We
are thus always happy to see more programs properly released under one
of our licenses. We can’t control the drafting by others of
proprietary software licenses, but we can and do forbid doing this in
a way that misleadingly associates those licenses with GNU or GNU
licenses.
We do not allow anyone to make unauthorized derivative works of our
licenses. We also do not allow and cannot accept confusing uses of the
FSF’s trademarks. We have allowed using the GPL’s terms to create
other licenses, but only under specified conditions, which are
stated in our FAQ. In such cases, using GPL terms to create new
licenses is permitted “provided that you call your license by another
name and do not include the GPL preamble, and provided you modify the
instructions-for-use at the end enough to make it clearly different in
wording and not mention GNU (though the actual procedure you describe
may be similar).”
Therefore, we are entitled to legally enforce our copyright and
trademark for FSF licenses that have been altered by added
restrictions to a verbatim GNU license. This enforcement activity is
different from enforcing the GPL against redistributors infringing by
not providing source code to users or otherwise releasing code that
violates the GPL. In the latter case, we follow “The Principles of
Community-Oriented GPL Enforcement.” We work towards compliance
with the GPL (and compliance with copyright law), but compliance in
that case also achieves, for that program, the ethical goal of the
free software movement: giving users the freedom to study, change and
redistribute the software they use. This is why legal action is our
last resort in GPL-compliance, and we instead focus mainly on
education and assistance.
Our work of enforcing our copyright and trademark rights against those
who attempt to draft proprietary licenses using our licenses
unfortunately does not necessarily result in free software. We
consider proprietary software unjust, but we have no legal power to
prohibit drafting proprietary licenses or applying them to software
one holds the copyright on. There is generally not a lot of value in
investing our energy in educating and assisting the drafters when
their goal is clearly to release nonfree software. Reasonably, we can
only demand that the drafters cease the actions that are confusing
people about the authenticity and intent of our licenses and about the
programs such proprietary licenses are applied to.
Nevertheless, in confronting infringement of our free licenses, we
follow similar principles of confidentiality. And similar to our other
compliance efforts, we also start with carefully verifying violations.
Needless to say, if it turns out that the restriction was added as a
mistake, or the software developer decides to release that program as
free software instead, we would be more than happy to accept the free
software release and a necessary public statement as sufficient remedy
to the infringement.
Proprietary software is ethically and morally wrong and we work hard
to build a future that holds less and less of it. Licenses that
confuse users about the freedoms they grant are damaging to the free
software movement because they threaten to dilute the value and power
of these licenses. When GNU licenses are misused through such
confusing practices, it harms the renown accrued by the GNU project
and the FSF over decades of free software advocacy. It is our duty to
all computer users to stop these practices, and, if necessary, we will
use our legal rights to this end.
