% FIXME: connecting text

\subsection{Additional Permissions}

The GPL is a statement of permissions, some of which have conditions.

Additional terms, terms that supplement those of the GPL, may come to be

placed on, or removed from, GPL-covered code in certain common ways.  We

consider those added terms ``additional permissions'' if they grant

exceptions from the conditions of the GPL, and ``additional requirements'' if

they add conditions to the basic permissions of the GPL. The treatment of

additional permissions and additional requirements under GPLv3 is necessarily

asymmetrical, because they do not raise the same ethical and interpretive

issues; in particular, additional requirements, if allowed without careful

limitation, could transform a GPL'd program into a non-free one.  With these

principles in the background, section 7 answers the following questions: (1)

How do the presence of additional terms on all or part of a GPL'd program

affect users' rights? (2) When and how may a licensee add terms to code being

distributed under the GPL? (3) When may a licensee remove additional terms?

% FIXME: FSF third person, etc.

Additional permissions present the easier case.  We have licensed some of our

own software under GPLv2 with permissive exceptions that allow combination

with non-free code, and that allow removal of those permissions by downstream

recipients; similarly, LGPLv2.1 is in essence a permissive variant of GPLv2,

and it permits relicensing under the GPL.  We have generalized these

practices in section 7.  A licensee may remove any additional permission from

a covered work, whether it was placed by the original author or by an

upstream distributor.  A licensee may also add any kind of additional

permission to any part of a work for which the licensee has, or can give,

appropriate copyright permission. For example, if the licensee has written

that part, the licensee is the copyright holder for that part and can

therefore give additional permissions that are applicable to it.

Alternatively, the part may have been written by someone else and licensed,

with the additional permissions, to that licensee.  Any additional

permissions on that part are, in turn, removable by downstream recipients.

As subsection 7a explains, the effect of an additional permission depends on

whether the permission applies to the whole work or a part.

% FIXME: rework this a bit

We have drafted version 3 of the GNU LGPL, which we have released with Draft

2 of GPLv3, as a simple list of additional permissions supplementing the

terms of GPLv3.  Section 7 has thus provided the basis for recasting a

formally complex license as an elegant set of added terms, without changing

any of the fundamental features of the existing LGPL.  We offer this draft of

LGPLv3 as as a model for developers wishing to license their works under the

GPL with permissive exceptions.  The removability of additional permissions

under section 7 does not alter any existing behavior of the LGPL; the LGPL

has always allowed relicensing under the ordinary GPL.

\subsection{Additional Requirements and License Compatibility}

% FIXME: minor rewrites needed

We broadened the title of section 7 because license compatibility, as it is

conventionally understood, is only one of several facets of the placement of

additional terms on GPL'd code.  The license compatibility issue arises for

three reasons.  First, the GPL is a strong copyleft license, requiring

modified versions to be distributed under the GPL.  Second, the GPL states

that no further restrictions may be placed on the rights of recipients.

Third, all other free software licenses in common use contain certain

requirements, many of which are not conditions made by the GPL.  Thus, when

GPL'd code is modified by combination with code covered by another formal

license that specifies other requirements, and that modified code is then

distributed to others, the freedom of recipients may be burdened by

additional requirements in violation of the GPL.  It can be seen that

additional permissions in other licenses do not raise any problems of license

compatibility.

% FIXME: minor rewrites needed

Section 7 relaxes the prohibition on further restrictions slightly by

enumerating, in subsection 7b, a limited list of categories of additional

requirements that may be placed on code without violating GPLv3.  The list

includes the items that were listed in Draft 1, though rewritten for clarity.

It also includes a new catchall category for terms that might not obviously

fall within one of the other categories but which are precisely equivalent to

GPLv3 conditions, or which deny permission for activities clearly not

permitted by GPLv3.  We have carefully considered but rejected proposals to

expand this list further.  We have also rejected suggestions, made by some

discussion committee members, that the Affero clause requirement (7d in Draft

1 and 7b4 in Draft 2) be removed, though we have revised it in response to

certain comments.  We are unwavering in our view that the Affero requirement

is a legitimate one, and we are committed to achieving compatibility of the

Affero GPL with GPLv3.

% FIXME: minor rewrites needed

A GPL licensee may place an additional requirement on code for which the

licensee has or can give appropriate copyright permission, but only if that

requirement falls within the list given in subsection 7b.  Placement of any

other kind of additional requirement continues to be a violation of the

license.  Additional requirements that are in the 7b list may not be removed,

but if a user receives GPL'd code that purports to include an additional

requirement not in the 7b list, the user may remove that requirement.  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.

% FIXME: minor rewrites needed

Section 7 points out that GPLv3 itself makes no assertion that an additional

requirement is enforceable by the copyright holder.  However, section 7 makes

clear that enforcement of such requirements is expected to be by the

termination procedure given in section 8 of GPLv3.

% FIXME: better context, etc.

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.