GPLv3~\S7  implements a more explicit policy on license

compatibility.  It formalizes the circumstances under which a licensee may

release a covered work that includes an added part carrying non-GPL terms. 

GPLv3~\S7 distinguish between terms that provide additional permissions, and terms that

place additional requirements on the code, relative to the permissions and

requirements established by applying the GPL to the code.

As discussed in the previous section of this tutorial, GPLv3~\S7 first and foremost explicitly allows added parts covered by terms with

additional permissions to be combined with GPL'd code. This codifies the

existing practice of regarding such licensing terms as compatible with the

GPL\@. A downstream user of a combined GPL'd work who modifies such an added

part may remove the additional permissions, in which case the broader

permissions no longer apply to the modified version, and only the terms of

the GPL apply to it.

In its treatment of terms that impose additional requirements, GPLv3\S7

extends the range of licensing terms with which the GPL is compatible.  An

added part carrying additional requirements may be combined with GPL'd code,

but only if those requirements belong to an set enumerated in GPLv3\S7. There

are, of course,  limits on the acceptable additional requirements, which to

ensures that enhanced license compatibility does not

defeat the broader software-freedom-defending terms of the GPL\@. Unlike terms that grant

additional permissions, terms that impose additional requirements cannot be

removed by a downstream user of the combined GPL'd work, because only in the

pathological case\footnote{Theoretically, a user could collect copyright

  assignment from all known contributors and then do this, but this would

  indeed be the pathological case.}  would a user have the right to do so.

% FIXME-LATER: It would be good to have detailed info on each of 7a-f.

%              Here's some commented-out text that might be useful for 7a-b

%% Under subsections 7a and 7b, the requirements may include preservation of

%% copyright notices, information about the origins of the code or alterations

%% of the code, and different warranty disclaimers. Under subsection 7c, the

%% requirements may include limitations on the use of names of contributors and

%% on the use of trademarks for publicity purposes. In general, we permit these

%% requirements in added terms because many free software licenses include them

%% and we consider them to be unobjectionable. Because we support trademark fair

%% use, the limitations on the use of trademarks may seek to enforce only what

%% is required by trademark law, and may not prohibit what would constitute fair

%% use.

% FIXME-LATER:  Say removing additional restrictions

% FIXME-LATER: This text may be useful later:

%% Some have questioned whether section 7 is needed, and some have suggested

%% that it creates complexity that did not previously exist.  We point out to

%% those readers that there is already GPLv2-licensed code that carries

%% additional terms.  One of the objectives of section 7 is to rationalize

%% existing practices of program authors and modifiers by setting clear

%% guidelines regarding the removal and addition of such terms.  With its

%% carefully limited list of allowed additional requirements, section 7

%% accomplishes additional objectives, permitting the expansion of the base of

%% code available for GPL developers, while also encouraging useful

%% experimentation with requirements we do not include in the GPL itself.

\section{GPLv3~\S8: A Lighter Termination}

GPLv2 provided for automatic termination of the rights of a person who

copied, modified, sublicensed, or distributed a work in violation of the

license.  Automatic termination can be too harsh for those who have committed

an inadvertent violation, particularly in cases involving distribution of

large collections of software having numerous copyright holders.  A violator

who resumes compliance with GPLv2 technically needs to obtain forgiveness

from all copyright holders, and even contacting them all might be impossible.

GPLv3~\S8 replaces now grants opportunities for provisional and permanent

reinstatement of rights. The termination procedure provides a limited

opportunity to cure license violations.  If a licensee has committed a

first-time violation of the GPL with respect to a given copyright holder, but

the licensee cures the violation within 30 days following receipt of notice

of the violation, then any of the licensee's GPL rights that have been

terminated by the copyright holder are ``automatically reinstated''.

Finally, if a licensee violates the GPL, a contributor may terminate any

patent licenses that it granted under GPLv3~\S11, in addition to any

copyright permissions the contributor granted to the licensee.

% FIXME-LATER: write more here, perhaps linking up to enforcement

\section{GPLv3~\S9: Acceptance}

GPLv3~\S9 means what it says: mere receipt or execution of code neither

requires nor signifies contractual acceptance under the GPL.  Speaking more

broadly, GPLv3 is intentionally structured our license as a unilateral grant

of copyright permissions, the basic operation of which exists outside of any

law of contract.  Whether and when a contractual relationship is formed

between licensor and licensee under local law do not necessarily matter to

the working of the license.

\section{GPLv3~\S10: Explicit Downstream License}

Careful readers of the GPL have suggested that its explicit prohibition

against imposition of further restrictions\footnote{GPLv2, section 6; Draft

  3, section 10, third paragraph.} has, or ought to have, implications for

those who assert patents against other licensees.  Draft 2 took some steps to

clarify this point in a manner not specific to patents, by describing the

imposition of ``a license fee, royalty, or other charge'' for exercising GPL

rights as one example of an impermissible further restriction.  In Draft 3 we

have clarified further that the requirement of non-imposition of further

restrictions has specific consequences for litigation accusing GPL-covered

programs of infringement.  Section 10 now states that ``you may not initiate

litigation (including a cross-claim or counterclaim in a lawsuit) alleging

that any patent claim is infringed by making, using, selling, offering for

sale, or importing the Program (or the contribution of any contributor).''

That is to say, a patent holder's licensed permissions to use a work under

GPLv3 may be terminated under section 8 if the patent holder files a lawsuit

alleging that use of the work, or of any upstream GPLv3-licensed work on

which the work is based, infringes a patent.

\section{GPLv3~\S11: Explicit Patent Licensing}

\label{GPLv3s11}

The patent licensing practices that section 7 of GPLv2 (corresponding to

section 12 of GPLv3) was designed to prevent are one of several ways in which

software patents threaten to make free programs non-free and to prevent users

from exercising their rights under the GPL. GPLv3 takes a more comprehensive

approach to combatting the danger of patents.

Software patenting is a harmful and unjust policy, and should be abolished;

recent experience makes this all the more evident. Since many countries grant

patents that can apply to and prohibit software packages, in various guises

and to varying degrees, we seek to protect the users of GPL-covered programs

from those patents, while at the same time making it feasible for patent

holders to contribute to and distribute GPL-covered programs as long as they

do not attack the users of those programs.

It is generally understood that GPLv2 implies some limits on a licensee's

power to assert patent claims against the use of GPL-covered works.

Therefore, we have designed GPLv3 to reduce the patent risks that distort and

threaten the activities of users who make, run, modify and share free

software.  At the same time, we have given due consideration to practical

goals such as certainty and administrability for patent holders that

participate in distribution and development of GPL-covered software.  Our

policy requires each such patent holder to provide appropriate levels of

patent assurance to users, according to the nature of the patent holder's

relationship to the program.

Draft 3 features several significant changes concerning patents.  We have

made improvements to earlier wording, clarified when patent assertion becomes

a prohibited restriction on GPL rights, and replaced a distribution-triggered

non-assertion covenant with a contribution-based patent license grant. We

have also added provisions to block collusion by patent holders with software

distributors that would extend patent licenses in a discriminatory way.

Draft 3 introduces the terms ``contributor'' and ``contribution,'' which are

used in the third paragraph of section 10 and the first paragraph of section

11, discussed successively in the following two subsections.  Section 0

defines a contributor as ``a party who licenses under this License a work on

which the Program is based.'' That work is the ``contribution'' of that

contributor.  In other words, each received GPLv3-covered work is associated

with one or more contributors, making up the finite set of upstream GPLv3

licensors for that work. Viewed from the perspective of a recipient of the

Program, contributors include all the copyright holders for the Program,

other than copyright holders of material originally licensed under non-GPL

terms and later incorporated into a GPL-covered work.  The contributors are

therefore the initial GPLv3 licensors of the Program and all subsequent

upstream licensors who convey, under the terms of section 5, modified works

on which the Program is based.

For a contributor whose contribution is a modified work conveyed under

section 5, the contribution is ``the entire work, as a whole'' which the

contributor is required to license under GPLv3.  The contribution therefore

includes not just the material added or altered by the contributor, but also

the pre-existing material the contributor copied from the upstream version

and retained in the modified version. Our usage of ``contributor'' and

``contribution'' should not be confused with the various other ways in which

those terms are used in certain other free software licenses.\footnote{Cf.,

  e.g., Apache License, version 2.0, section 1; Eclipse Public License,

  version 1.0, section 1; Mozilla Public License, version 1.1, section 1.1.}

The term ``patent license,'' as used in the third through fifth

paragraphs of section 11, is not meant to be confined to agreements

formally identified or classified as patent licenses.  The new second

paragraph of section 11 makes this clear by defining ``patent license,''

for purposes of the subsequent three paragraphs, as ``a patent license,

a covenant not to bring suit for patent infringement, or any other

express agreement or commitment, however denominated, not to enforce a

patent.''  The definition does not include patent licenses that arise by

implication or operation of law, because the third through fifth

paragraphs of section 11 are specifically concerned with explicit

promises that purport to be legally enforceable.

Our previous drafts featured a patent license grant triggered by all

acts of distribution of GPLv3-covered works.\footnote{In Draft 2 we

rewrote the patent license as a covenant not to assert patent claims. We

explain why we reverted to the form of a patent license grant in \S\

\ref{cov}.} Many patent-holding companies objected to this policy. They

have made two objections: (1) the far-reaching impact of the patent

license grant on the patent holder is disproportionate to the act of

merely distributing code without modification or transformation, and (2)

it is unreasonable to expect an owner of vast patent assets to exercise

requisite diligence in reviewing all the GPL-covered software that it

provides to others.  Some expressed particular concern about the

consequences of ``inadvertent'' distribution.

The argument that the impact of the patent license grant would be

``disproportionate,'' that is to say unfair, is not valid. Since

software patents are weapons that no one should have, and using them for

aggression against free software developers is an egregious act,

preventing that act cannot be unfair. 

However, the second argument seems valid in a practical sense.  A

typical GNU/Linux distribution includes thousands of programs. It would

be quite difficult for a redistributor with a large patent portfolio to

review all those programs against that portfolio every time it receives

and passes on a new version of the distribution. Moreover, this question