Copyleft/guide Changeset - f8a919928413

...

@@ -3396,471 +3396,468 @@ In other words, the ``contributor version'' 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.  (GPLv3's 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.}.)

Some details of the ``essential patent claims'' definition deserve special

mention.  ``Essential patent claims'', for a given party, are a subset of the

claims ``owned or controlled'' by the party.  They do include sublicensable

claims that have been licensed to the contributor by a third

party.\footnote{This issue is typically handled in other software freedom

  licenses having patent licensing provisions by use of the unhelpful term

  ``licensable,'' which is either left undefined or is given an ambiguous

  definition.}  Most commercial patent license agreements that permit

sublicensing do so under restrictive terms that are inconsistent with the

requirements of the GPL\@.  For example, some patent licenses allow the

patent licensee to sublicense but require collection of royalties from any

sublicensees.  The patent licensee could not distribute a GPL-covered program

and grant the recipient a patent sublicense for the program without violating

section 12 of GPLv3.\footnote{GPLv3 also provides an example in section 12

  that makes this point clear.}  In rare cases, however, a conveying party

can freely grant patent sublicenses to downstream recipients without

violating the GPL\@.

Additionally, ``essential patent claims'' are those patents ``that would be

infringed by some manner, permitted by this License, of making, using, or

selling the work''.  This intends to make clear that a patent claim is

``essential'' if some mode of usage would infringe that claim, even if there

are other modes of usage that would not infringe.

Finally, ``essential patent claims \ldots do not include

claims that would be infringed only as a consequence of further

modification of the work.''  The set of essential patent

claims licensed  is fixed by the

the particular version of the work that was contributed.  The claim set

cannot expand as a work is further modified downstream.  (If it could,

then any software patent claim would be included, since any software

patent claim can be infringed by some further modification of the

work.)\footnote{However, ``the work'' should not be understood to be

restricted to a particular mechanical affixation of, or medium for

distributing, a program, where the same program might be provided in

other forms or in other ways that may be captured by other patent claims

held by the contributor.}

\medskip

Ideally, this contributor patent policy will result in fairly frequent licensing of patent

claims by contributors.  A contributor is charged with awareness of the fact

that it has modified a work and provided it to others; no act of contribution

should be treated as inadvertent.  GPLv3's rule also requires no more work, for a

contributor, than the weaker rule proposed by the patent holders.  Under

their rule, the contributor must always compare the entire work against its

patent portfolio to determine whether the combination of the modifications

with the remainder of the work cause it to read on any of the contributor's

patent claims.

\subsection{Conveyors' Patent Licensing}

The remaining patent licensing in GPLv3 deals with patent licenses that are

granted by conveyance.  The licensing is not as complete or far reaching at

the contributor patent licenses discussed in the preceding section.

The term ``patent license,'' as used in GPLv3~\S11\P4--6, is not meant to be

confined to agreements formally identified or classified as patent licenses.

GPLv3~\S11\P3  makes this clear by defining ``patent

license,'' for purposes of the subsequent three paragraphs, as ``any express

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

(such as an express permission to practice a patent or covenant not to

sue for patent infringement)''

% FIME-LATER: I want to ask Fontana about this before adding it.

% 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.

GPLv3~\S11\P5 is commonly called GPLv3's downstream shielding provision.  It

responds particularly to the problem of exclusive deals between patent

holders and distributors, which threaten to distort the free software

distribution system in a manner adverse to developers and users.  The

fundamental idea is to make a trade-off between assuring a patent license for

downstream and making  (possibly patent-encumbered) CCS publicly available.

Simply put, in nearly all cases in which the ``knowingly relying'' test is

met, the patent license will indeed not be sublicensable or generally

available to all on free terms.  If, on the other hand, the patent license is

generally available under terms consistent with the requirements of the GPL,

the distributor is automatically in compliance, because the patent license

has already been extended to all downstream recipients.  Finally, if the

patent license is sublicensable on GPL-consistent terms, the distributor may

choose to grant sublicenses to downstream recipients instead of causing the

CCS to be publicly available.  (In such a case, if the distributor is also a

contributor, it will already have granted a patent sublicense anyway, and so

it need not do anything further to comply with the third paragraph.)

Admittedly, public disclosure of CCS is not necessarily required in by other

sections of the GPL, and the FSF in drafting GPLv3 did not necessarily wish

to impose a general requirement to make source code available to all, which

has never been a GPL condition.  However, many vendors who produce products

that include copylefted software, and who most likely to be affected by the

downstream shielding provision, lobbied for the addition of the source code

availability option, so it remains.

Meanwhile, two specific alternatives to the source code availability option

are also available. The distributor may comply by disclaiming the patent

license it has been granted for the conveyed work, or by arranging to extend

the patent license to downstream recipients\footnote{The latter option, if

  chosen, must be done ``in a manner consistent with the requirements of this

  License''; for example, it is unavailable if extension of the patent

  license would result in a violation of GPLv3~\S 12.}.  The GPL is intended

to permit private distribution as well as public distribution, and the

addition of these options ensures that this remains the case, even though it

remains likely that distributors in this situation will usually choose the

source code availability option.

Note that GPLv3~\S11\P5 is activated only if the CCS is not already otherwise

publicly available.  (Most often it will, in fact, already be available on

some network server operated by a third party.)  Even if it is not already

available, the option to ``cause the Corresponding Source to be so

available'' can then be satisfied by verifying that a third party has acted

to make it available.  That is to say, the affected distributor need not

itself host the CCS to take advantage of the source code availability option.

This subtlety may help the distributor avoid certain peculiar assumptions of

liability.

Note that GPLv3~\S11\P6--7 are designed to stop distributors from colluding with

third parties to offer selective patent protection.  GPLv3 is designed to

ensure that all users receive the same rights; arrangements that circumvent

this make a mockery of free software, and we must do everything in our power

to stop them.

First, GPLv3~\S11\P6 states that any license that protects some recipients of

GPLed software must be extended to all recipients of the software.

If conveyors arrange to provide patent

protection to some of the people who get the software from you, that

protection is automatically extended to everyone who receives the software,

no matter how they get it.

Second, GPLv3~\S11\P7

prohibit anyone who made such an agreement from distributing software

released under GPLv3.    Conveyors are prohibited from

distributing software under GPLv3 if the conveyor makes an agreement of that

nature in the future.

The date in GPLv3~\S11\P7 likely seems arbitrary to those who did not follow

the GPLv3 drafting process.  This issue was hotly debated during the drafting of

GPLv3, but ultimately one specific deal of this type --- a deal between Microsoft

and Novell for Microsoft to provide so-called ``coupons'' to Microsoft customers to redeem

for copies of Novell's GNU/Linux distribution with a Microsoft patent license -- was

designed to be excluded.

The main reason for this was a tactical decision by the FSF.  FSF believed they can do more to

protect the community by allowing Novell to use software under GPLv3

than by forbidding it to do so.  This is because of

paragraph 6 of section 11 (corresponding to paragraph 4 in Draft 3).

It will apply, under the Microsoft/Novell deal, because of the coupons

that Microsoft has acquired that essentially commit it to participate

in the distribution of the Novell SLES GNU/Linux system.

The FSF also gave a secondary reason:  to avoid affecting other kinds of agreements for

other kinds of activities.  While GPLv3 sought to

distinguish pernicious deals of the Microsoft/Novell type from

business conduct that is not particularly harmful, the FSF also did not

assume success in that drafting, and thus there remained some risk that other

unchangeable past agreements could fall within the  scope of GPLv3~\S11\P7.

In future deals, distributors engaging in ordinary business practices

can structure the agreements so that they do not fall under GPLv3~\S11\P7.

\section{GPLv3~\S12: Familiar as GPLv2~\S7}

GPLv2~\S12 remains almost completely unchanged from the text that appears

GPLv2~\S7.  This is an important provision that ensures a catch-all to ensure

that nothing ``surprising'' interferes with the continued conveyance safely

under copyleft.

The wording in the first sentence of GPLv3~\S12 has been revised slightly to

clarify that an agreement -- such as a litigation settlement agreement or a

patent license agreement -- is one of the ways in which conditions may be

``imposed'' on a GPL licensee that may contradict the conditions of the GPL,

but which do not excuse the licensee from compliance with those conditions.

This change codifies the historical interpretation of GPLv2.

GPLv3 removed the limited severability clause of GPLv2~\S7 as a

matter of tactical judgment, believing that this is the best way to ensure

that all provisions of the GPL will be upheld in court. GPLv3 also removed

the final sentence of GPLv2 section 7, which the FSF consider to be unnecessary.

\section{GPLv3~\S13: The Great Affero Compromise}

The main purpose of clause 7b4 was to attain GPLv3 compatibility for the

additional condition of version 1 of the Affero GPL, with a view to

achieving compatibility for a future version, since version 1 was

incompatible with GPLv3.\footnote{Version 1 of the Affero GPL contains

its own copyleft clause, worded identically to that in GPLv2, which

conflicts with the copyleft clause in GPLv3.  The Affero GPL permits

relicensing under versions of the GPL later than version 2, but only if

the later version ``includes terms and conditions substantially

equivalent to those of this license'' (Affero GPL, version 1, section

9). The Affero license was written with the expectation that its

The Affero GPL was written with the expectation that its

additional requirement would be incorporated into the terms of GPLv3

itself, rather than being placeable on parts added to a covered work

through the mechanism of section 7 of GPLv3.}  However, we wrote the

clause broadly enough to cover a range of other possible terms that

would differ from the Affero condition in their details. Draft 3 no

longer pursues the more ambitious goal of allowing compatibility for a

whole category of Affero-like terms.  In place of 7b4, we have added a

new section 13 that simply permits GPLv3-covered code to be linked with

code covered by the forthcoming version 2 of the Affero GPL.

We have made this decision in the face of irreconcilable views from

different parts of our community.  While we had known that many

commercial users of free software were opposed to the inclusion of a

mandatory Affero-like requirement in the body of GPLv3 itself, we were

surprised at their opposition to its availability through section 7.

Free software vendors allied to these users joined in their objections,

as did a number of free software developers arguing on ethical as well

as practical grounds.

Some of this hostility seemed to be based on a misapprehension that

Affero-like terms placed on part of a covered work would somehow extend

to the whole of the work.\footnote{It is possible that the presence of

the GPLv2-derived copyleft clause in the existing Affero GPL contributed

to this misunderstanding.}  Our explanations to the contrary did little

to satisfy these critics; their objections to 7b4 instead evolved into a

broader indictment of the additional requirements scheme of section 7.

It was clear, however, that much of the concern about 7b4 stemmed from

its general formulation.  Many were alarmed at the prospect of GPLv3

compatibility for numerous Affero-like licensing conditions,

unpredictable in their details but potentially having significant

commercial consequences.

On the other hand, many developers, otherwise sympathetic to the policy

goals of the Affero GPL, have objected to the form of the additional

requirement in that license.  These developers were generally

disappointed with our decision to allow Affero-like terms through

section 7, rather than adopt a condition for GPLv3.  Echoing their

concerns about the Affero GPL itself, they found fault with the wording

of the section 7 clause in both of the earlier drafts.  We drafted 7b4

at a higher level than its Draft 1 counterpart based in part on comments

from these developers. They considered the Draft 1 clause too closely

tied to the Affero mechanism of preserving functioning facilities for

downloading source, which they found too restrictive of the right of

modification.  The 7b4 rewording did not satisfy them, however. They

objected to its limitation to terms requiring compliance by network

transmission of source, and to the technically imprecise or inaccurate

use of the phrase ``same network session.''

We have concluded that any redrafting of the 7b4 clause would fail to

satisfy the concerns of both sets of its critics.  The first group

maintains that GPLv3 should do nothing about the problem of public

use. The second group would prefer for GPLv3 itself to have an

Affero-like condition, but that seems to us too drastic. By permitting

GPLv3-covered code to be linked with code covered by version 2 of the

Affero GPL, the new section 13 honors our original commitment to

achieving GPL compatibility for the Affero license.

Version 2 of the Affero GPL is not yet published.  We will work with

Affero, Inc., and with all other interested members of our community, to

complete the drafting of this license following the release of Draft 3,

with a goal of having a final version available by the time of our

adoption of the final version of GPLv3.  We hope the new Affero license

will satisfy those developers who are concerned about the issue of

public use of unconveyed versions but who have concerns about the

narrowness of the condition in the existing Affero license.

As the second sentence in section 13 indicates, when a combined work is

made by linking GPLv3-covered code with Affero-covered code, the

copyleft on one part will not extend to the other part.\footnote{The

plan is that the additional requirement of the new Affero license will

state a reciprocal limitation.} That is to say, in such combinations,

the Affero requirement will apply only to the part that was brought into

the combination under the Affero license.  Those who receive such a

combination and do not wish to use code under the Affero requirement may

remove the Affero-covered portion of the combination.

Those who criticize the permission to link with code under the Affero

itself.  Many software freedom advocates, including some authors of this

tutorial, advocated heavily for that, and fully expected it to happen.

The FSF, however, chose not to include the Affero clause in GPLv3, due to

what it called  ``irreconcilable views from

different parts of the community''.  Many

commercial users of Free Software were opposed to the inclusion of a

mandatory Affero-like requirement in the body of GPLv3 itself.  In fact, some

wealthier companies even threatened to permanently fund forks of many FSF

copyrighted-programs under GPLv2 if the Affero clause appeared in GPLv3.

Meanwhile, there was disagreement even among copyleft enthusiasts about the

importance of the provision.  A coalition never formed, and ultimately the

more powerful interest implicitly allied with the companies who deeply opposed

the Affero clause such that the FSF felt the Affero clause would need its own

license, but one compatible with GPLv3.

GPLv3~\S13 makes GPLv3 compatible with the AGPLv3, so that at least code can

be shared between AGPLv3'd and GPLv3' projects, even if the Affero clause

does not automatically apply to all GPLv3'd works.

%FIXME-LATER:  no time to do this justice, will come back later, instead the

%above.

%% Some of this hostility seemed to be based on a misapprehension that

%% Affero-like terms placed on part of a covered work would somehow extend

%% to the whole of the work.\footnote{It is possible that the presence of

%% the GPLv2-derived copyleft clause in the existing Affero GPL contributed

%% to this misunderstanding.}  Our explanations to the contrary did little

%% to satisfy these critics; their objections to 7b4 instead evolved into a

%% broader indictment of the additional requirements scheme of section 7.

%% It was clear, however, that much of the concern about 7b4 stemmed from

%% its general formulation.  Many were alarmed at the prospect of GPLv3

%% compatibility for numerous Affero-like licensing conditions,

%% unpredictable in their details but potentially having significant

%% commercial consequences.

%% On the other hand, many developers, otherwise sympathetic to the policy

%% goals of the Affero GPL, have objected to the form of the additional

%% requirement in that license.  These developers were generally

%% disappointed with our decision to allow Affero-like terms through

%% section 7, rather than adopt a condition for GPLv3.  Echoing their

%% concerns about the Affero GPL itself, they found fault with the wording

%% of the section 7 clause in both of the earlier drafts.  We drafted 7b4

%% at a higher level than its Draft 1 counterpart based in part on comments

%% from these developers. They considered the Draft 1 clause too closely

%% tied to the Affero mechanism of preserving functioning facilities for

%% downloading source, which they found too restrictive of the right of

%% modification.  The 7b4 rewording did not satisfy them, however. They

%% objected to its limitation to terms requiring compliance by network

%% transmission of source, and to the technically imprecise or inaccurate

%% use of the phrase ``same network session.''

%% We have concluded that any redrafting of the 7b4 clause would fail to

%% satisfy the concerns of both sets of its critics.  The first group

%% maintains that GPLv3 should do nothing about the problem of public

%% use. The second group would prefer for GPLv3 itself to have an

%% Affero-like condition, but that seems to us too drastic. By permitting

%% GPLv3-covered code to be linked with code covered by version 2 of the

%% Affero GPL, the new section 13 honors our original commitment to

%% achieving GPL compatibility for the Affero license.

%% Version 2 of the Affero GPL is not yet published.  We will work with

%% Affero, Inc., and with all other interested members of our community, to

%% complete the drafting of this license following the release of Draft 3,

%% with a goal of having a final version available by the time of our

%% adoption of the final version of GPLv3.  We hope the new Affero license

%% will satisfy those developers who are concerned about the issue of

%% public use of unconveyed versions but who have concerns about the

%% narrowness of the condition in the existing Affero license.

%% As the second sentence in section 13 indicates, when a combined work is

%% made by linking GPLv3-covered code with Affero-covered code, the

%% copyleft on one part will not extend to the other part.\footnote{The

%% plan is that the additional requirement of the new Affero license will

%% state a reciprocal limitation.} That is to say, in such combinations,

%% the Affero requirement will apply only to the part that was brought into

%% the combination under the Affero license.  Those who receive such a

%% combination and do not wish to use code under the Affero requirement may

%% remove the Affero-covered portion of the combination.

Meanwhile, those who criticize the permission to link with code under the Affero

GPL should recognize that most other free software licenses also permit

such linking.

\section{GPLv3~\S14: So, When's GPLv4?}

\label{GPLv3s14}

% FIXME Say more

No substantive change has been made in section 14. The wording of the section

has been revised slightly to make it clearer.

% FIXME; proxy

\section{GPLv3~\S15--17: Warranty Disclaimers and Liability Limitation}

No substantive changes have been made in sections 15 and 16.

% FIXME: more, plus 17

% FIXME: Section header needed here about choice of law.

% FIXME: reword into tutorial

Some have asked us to address the difficulties of internationalization

by including, or permitting the inclusion of, a choice of law

provision.  We maintain that this is the wrong approach.  Free

software licenses should not contain choice of law clauses, for both

legal and pragmatic reasons.  Choice of law clauses are creatures of

contract, but the substantive rights granted by the GPL are defined

under applicable local copyright law. Contractual free software

licenses can operate only to diminish these rights.  Choice of law

clauses also raise complex questions of interpretation when works of

software are created by combination and extension.  There is also the

real danger that a choice of law clause will specify a jurisdiction

that is hostile to free software principles.

% FIXME: reword into tutorial, \ref to section 7.

Our revised version of section 7 makes explicit our view that the

inclusion of a choice of law clause by a licensee is the imposition of

an additional requirement in violation of the GPL.  Moreover, if a

program author or copyright holder purports to supplement the GPL with

a choice of law clause, section 7 now permits any licensee to remove

that clause.

% FIXME: does this need to be a section, describing how it was out then in

% then out then in? :)

We have removed from this draft the appended section on ``How to Apply These

Terms to Your New Programs.'' For brevity, the license document can instead

refer to a web page containing these instructions as a separate document.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\chapter{The Lesser GPL}

As we have seen in our consideration of the GPL, its text is specifically

designed to cover all possible derivative works under copyright law. Our

goal in designing GPL was to make sure that any derivative work of GPL'd

software was itself released under GPL when distributed. Reaching as far

as copyright law will allow is the most direct way to reach that goal.

However, while the strategic goal is to bring as much Free Software

into the world as possible, particular tactical considerations

regarding software freedom dictate different means. Extending the

copyleft effect as far as copyright law allows is not always the most

prudent course in reaching the goal. In particular situations, even

those of us with the goal of building a world where all published

software is Free Software realize that full copyleft does not best

serve us. The GNU Lesser General Public License (``GNU LGPL'') was

designed as a solution for such situations.

\section{The First LGPL'd Program}

The first example that FSF encountered where such altered tactics were

needed was when work began on the GNU C Library. The GNU C Library would

become (and today, now is) a drop-in replacement for existing C libraries.

On a Unix-like operating system, C is the lingua franca and the C library

is an essential component for all programs. It is extremely difficult to

construct a program that will run with ease on a Unix-like operating

system without making use of services provided by the C library --- even

if the program is written in a language other than C\@. Effectively, all

user application programs that run on any modern Unix-like system must

make use of the C library.

By the time work began on the GNU implementation of the C libraries, there

were already many C libraries in existence from a variety of vendors.

Every proprietary Unix vendor had one, and many third parties produced

smaller versions for special purpose use. However, our goal was to create

a C library that would provide equivalent functionality to these other C

libraries on a Free Software operating system (which in fact happens today

on modern GNU/Linux systems, which all use the GNU C Library).

Unlike existing GNU application software, however, the licensing

implications of releasing the GNU C Library (``glibc'') under GPL were

somewhat different. Applications released under GPL would never

themselves become part of proprietary software. However, if glibc were

released under GPL, it would require that any application distributed for

the GNU/Linux platform be released under GPL\@.

Since all applications on a Unix-like system depend on the C library, it

means that they must link with that library to function on the system. In

other words, all applications running on a Unix-like system must be

combined with the C library to form a new whole derivative work that is

composed of the original application and the C library. Thus, if glibc

were GPL'd, each and every application distributed for use on GNU/Linux

would also need to be GPL'd, since to even function, such applications

would need to be combined into larger derivative works by linking with

glibc.

At first glance, such an outcome seems like a windfall for Free Software

advocates, since it stops all proprietary software development on

GNU/Linux systems. However, the outcome is a bit more subtle. In a world

where many C libraries already exist, many of which could easily be ported

to GNU/Linux, a GPL'd glibc would be unlikely to succeed. Proprietary

vendors would see the excellent opportunity to license their C libraries

to anyone who wished to write proprietary software for GNU/Linux systems.

The de-facto standard for the C library on GNU/Linux would likely be not

glibc, but the most popular proprietary one.

Meanwhile, the actual goal of releasing glibc under GPL --- to ensure no

proprietary applications on GNU/Linux --- would be unattainable in this

scenario. Furthermore, users of those proprietary applications would also

be users of a proprietary C library, not the Free glibc.

The Lesser GPL was initially conceived to handle this scenario. It was

clear that the existence of proprietary applications for GNU/Linux was

inevitable. Since there were so many C libraries already in existence, a

new one under GPL would not stop that tide. However, if the new C library

were released under a license that permitted proprietary applications

to link with it, but made sure that the library itself remained Free,

an ancillary goal could be met. Users of proprietary applications, while

they would not have the freedom to copy, share, modify and redistribute

the application itself, would have the freedom to do so with respect to

the C library.

There was no way the license of glibc could stop or even slow the creation

of proprietary applications on GNU/Linux. However, loosening the

restrictions on the licensing of glibc ensured that nearly all proprietary

applications at least used a Free C library rather than a proprietary one.

This trade-off is central to the reasoning behind the LGPL\@.

Of course, many people who use the LGPL today are not thinking in these

terms. In fact, they are often choosing the LGPL because they are looking

for a ``compromise'' between the GPL and the X11-style liberal licensing.

However, understanding FSF's reasoning behind the creation of the LGPL is

helpful when studying the license.

\section{What's the Same?}

Much of the text of the LGPL is identical to the GPL\@. As we begin our

discussion of the LGPL, we will first eliminate the sections that are

identical, or that have the minor modification changing the word

``Program'' to ``Library.''

First, LGPLv2.1~\S1, the rules for verbatim copying of source, are

equivalent to those in GPLv2~\S1.

Second, LGPLv2.1~\S8 is equivalent GPLv2~\S4\@. In both licenses, this

section handles termination in precisely the same manner.

LGPLv2.1~\S9 is equivalent to GPLv2~\S5\@. Both sections assert that

the license is a copyright license, and handle the acceptance of those

copyright terms.

LGPLv2.1~\S10 is equivalent to GPLv2~\S6. They both protect the

distribution system of Free Software under these licenses, to ensure that

up, down, and throughout the distribution chain, each recipient of the

software receives identical rights under the license and no other

restrictions are imposed.

LGPLv2.1~\S11 is GPLv2~\S7. As discussed, it is used to ensure that

other claims and legal realities, such as patent licenses and court

judgments, do not trump the rights and permissions granted by these

licenses, and requires that distribution be halted if such a trump is

known to exist.

LGPLv2.1~\S12 adds the same features as GPLv2~\S8. These sections are

used to allow original copyright holders to forbid distribution in

countries with draconian laws that would otherwise contradict these

licenses.

LGPLv2.1~\S13 sets up FSF as the steward of the LGPL, just as GPLv2~\S9

does for GPL. Meanwhile, LGPLv2.1~\S14 reminds licensees that copyright

holders can grant exceptions to the terms of LGPL, just as GPLv2~\S10

reminds licensees of the same thing.

Finally, the assertions of no warranty and limitations of liability are

identical; thus LGPLv2.1~\S15 and LGPLv2.1~\S16 are the same as GPLv2~\S11 and \S

12.