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<chapter xml:id="LPPL:LPPL" version="1.3c" xml:lang="en:US"
  revision="2008-05-04" annotations="Copyright 1999, 2002--2008
  &LaTeX3; Project">
  <title>The &LaTeX; Project Public License</title>
  <blockquote>
    <para>Everyone is allowed to distribute verbatim copies of this
      license document, but modification of it is not allowed.</para>
  </blockquote>
  <sect1 xml:id="LPPL:Preamble">
    <title>Preamble</title>
    <para>The &LaTeX; Project Public License (<acronym>LPPL</acronym>)
      is the primary license under which the &LaTeX; kernel and the
      base &LaTeX; packages are distributed.</para>
    <para>You may use this license for any work of which you hold the
      copyright and which you wish to distribute.  This license may be
      particularly suitable if your work is &TeX;-related (such as a
      &LaTeX; package), but it is written in such a way that you can
      use it even if your work is unrelated to &TeX;.</para>
    <para>The section <citetitle linkend="LPPL:Distribute"
	pubwork="section"/>, below, gives instructions, examples, and
      recommendations for authors who are considering distributing
      their works under this license.</para>
    <para>This license gives conditions under which a work may be
      distributed and modified, as well as conditions under which
      modified versions of that work may be distributed.</para>
    <para>We, the &LaTeX3; Project, believe that the conditions below
      give you the freedom to make and distribute modified versions of
      your work that conform with whatever technical specifications
      you wish while maintaining the availability, integrity, and
      reliability of that work.  If you do not see how to achieve your
      goal while meeting these conditions, then read the document
      <filename xlink:type="tex">cfgguide</filename> and <filename
	xlink:type="tex">modguide</filename> in the base &LaTeX;
      distribution for suggestions.</para>
  </sect1>
  <sect1 xml:id="LPPL:Definitions">
    <title>Definitions</title>
    <para>In this license document the following terms are used:</para>
    <variablelist>
      <varlistentry>
	<term>Work</term>
	<listitem>
	  <para>Any work being distributed under this License.</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term>Derived Work</term>
	<listitem>
	  <para>Any work that under any applicable law is derived from
	    the Work.</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term>Modification</term>
	<listitem>
	  <para>Any procedure that produces a Derived Work under any
	    applicable law&mdash;for example, the production of a file
	    containing an original file associated with the Work or a
	    significant portion of such a file, either verbatim or
	    with modifications and/or translated into another
	    language.</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term>Modify</term>
	<listitem>
	  <para>To apply any procedure that produces a Derived Work
	    under any applicable law.</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term>Distribution</term>
	<listitem>
	  <para>Making copies of the Work available from one person to
	    another, in whole or in part.  Distribution includes (but
	    is not limited to) making any electronic components of the
	    Work accessible by file transfer protocols such as
	    <acronym>FTP</acronym> or <acronym>HTTP</acronym> or by
	    shared file systems such as Sun's Network File System
	    (<acronym>NFS</acronym>).</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term>Compiled Work</term>
	<listitem>
	  <para>A version of the Work that has been processed into a
	    form where it is directly usable on a computer system.
	    This processing may include using installation facilities
	    provided by the Work, transformations of the Work, copying
	    of components of the Work, or other activities.  Note that
	    modification of any installation facilities provided by
	    the Work constitutes modification of the Work.</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term>Current Maintainer</term>
	<listitem>
	  <para>A person or persons nominated as such within the Work.
	    If there is no such explicit nomination then it is the
	    <phrase>Copyright Holder</phrase> under any applicable
	    law.</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term>Base Interpreter</term>
	<listitem>
	  <para>A program or process that is normally needed for
	    running or interpreting a part or the whole of the
	    Work.</para>
	  <para>A Base Interpreter may depend on external components
	    but these are not considered part of the Base Interpreter
	    provided that each external component clearly identifies
	    itself whenever it is used interactively.  Unless
	    explicitly specified when applying the license to the
	    Work, the only applicable Base Interpreter is a
	    <phrase>&LaTeX;-Format</phrase> or in the case of files
	    belonging to the <phrase>&LaTeX;-format</phrase> a program
	    implementing the `&TeX; language'.</para>
	</listitem>
      </varlistentry>
    </variablelist>
  </sect1>
  <sect1 xml:id="LPPL:Conditions">
    <title>Conditions on Distribution and Modification</title>
    <orderedlist>
      <listitem>
	<para>Activities other than distribution and/or modification
	  of the Work are not covered by this license; they are
	  outside its scope. In particular, the act of running the
	  Work is not restricted and no requirements are made
	  concerning any offers of support for the Work.</para>
      </listitem>
      <listitem xml:id="LPPL:item:distribute">
	<para>You may distribute a complete, unmodified copy of the
	  Work as you received it.  Distribution of only part of the
	  Work is considered modification of the Work, and no right to
	  distribute such a Derived Work may be assumed under the
	  terms of this clause.</para>
      </listitem>
      <listitem>
	<para>You may distribute a Compiled Work that has been
	  generated from a complete, unmodified copy of the Work as
	  distributed under Clause&nbsp;<xref
	    linkend="LPPL:item:distribute"/> above, as
	  long as that Compiled Work is distributed in such a way that
	  the recipients may install the Compiled Work on their system
	  exactly as it would have been installed if they generated a
	  Compiled Work directly from the Work.</para>
      </listitem>
      <listitem xml:id="LPPL:item:currmaint">
	<para>If you are the Current Maintainer of the Work, you may,
	  without restriction, modify the Work, thus creating a
	  Derived Work.  You may also distribute the Derived Work
	  without restriction, including Compiled Works generated from
	  the Derived Work.  Derived Works distributed in this manner
	  by the Current Maintainer are considered to be updated
	  versions of the Work.</para>
      </listitem>
      <listitem>
	<para>If you are not the Current Maintainer of the Work, you
	  may modify your copy of the Work, thus creating a Derived
	  Work based on the Work, and compile this Derived Work, thus
	  creating a Compiled Work based on the Derived Work.</para>
      </listitem>
      <listitem xml:id="LPPL:item:conditions">
	<para>If you are not the Current Maintainer of the Work, you
	  may distribute a Derived Work provided the following
	  conditions are met for every component of the Work unless
	  that component clearly states in the copyright notice that
	  it is exempt from that condition.  Only the Current
	  Maintainer is allowed to add such statements of exemption to
	  a component of the Work.</para>
	<orderedlist>
	  <listitem>
	    <para>If a component of this Derived Work can be a direct
	      replacement for a component of the Work when that
	      component is used with the Base Interpreter, then,
	      wherever this component of the Work identifies itself to
	      the user when used interactively with that Base
	      Interpreter, the replacement component of this Derived
	      Work clearly and unambiguously identifies itself as a
	      modified version of this component to the user when used
	      interactively with that Base Interpreter.</para>
	  </listitem>
	  <listitem>
	    <para>Every component of the Derived Work contains
	      prominent notices detailing the nature of the changes to
	      that component, or a prominent reference to another file
	      that is distributed as part of the Derived Work and that
	      contains a complete and accurate log of the
	      changes.</para>
	  </listitem>
	  <listitem>
	    <para>No information in the Derived Work implies that any
	      persons, including (but not limited to) the authors of
	      the original version of the Work, provide any support,
	      including (but not limited to) the reporting and
	      handling of errors, to recipients of the Derived Work
	      unless those persons have stated explicitly that they do
	      provide such support for the Derived Work.</para>
	  </listitem>
	  <listitem>
	    <para>You distribute at least one of the following with
	      the Derived Work:</para>
	    <orderedlist>
	      <listitem>
		<para>A complete, unmodified copy of the Work; if your
		  distribution of a modified component is made by
		  offering access to copy the modified component from
		  a designated place, then offering equivalent access
		  to copy the Work from the same or some similar place
		  meets this condition, even though third parties are
		  not compelled to copy the Work along with the
		  modified component;</para>
	      </listitem>
	      <listitem>
		<para>Information that is sufficient to obtain a
		  complete, unmodified copy of the Work.</para>
	      </listitem>
	    </orderedlist>
	  </listitem>
	</orderedlist>
      </listitem>
      <listitem>
	<para>If you are not the Current Maintainer of the Work, you
	  may distribute a Compiled Work generated from a Derived
	  Work, as long as the Derived Work is distributed to all
	  recipients of the Compiled Work, and as long as the
	  conditions of Clause&nbsp;<xref
	    linkend="LPPL:item:conditions"/>, above, are met
	  with regard to the Derived Work.</para>
      </listitem>
      <listitem>
	<para>The conditions above are not intended to prohibit, and
	  hence do not apply to, the modification, by any method, of
	  any component so that it becomes identical to an updated
	  version of that component of the Work as it is distributed
	  by the Current Maintainer under Clause&nbsp;<xref
	    linkend="LPPL:item:currmaint"/>, above.</para>
      </listitem>
      <listitem>
	<para>Distribution of the Work or any Derived Work in an
	  alternative format, where the Work or that Derived Work (in
	  whole or in part) is then produced by applying some process
	  to that format, does not relax or nullify any sections of
	  this license as they pertain to the results of applying that
	  process.</para>
      </listitem>
      <listitem>
	<orderedlist>
	  <listitem>
	    <para>A Derived Work may be distributed under a different
	      license provided that license itself honors the
	      conditions listed in Clause&nbsp;<xref
		linkend="LPPL:item:conditions"/> above, in
	      regard to the Work, though it does not have to honor the
	      rest of the conditions in this license.</para>
	  </listitem>
	  <listitem>
	    <para>If a Derived Work is distributed under a different
	      license, that Derived Work must provide sufficient
	      documentation as part of itself to allow each recipient
	      of that Derived Work to honor the restrictions in
	      Clause&nbsp;<xref
		linkend="LPPL:item:conditions"/> above, concerning
	      changes from the Work.</para>
	  </listitem>
	</orderedlist>
      </listitem>
      <listitem>
	<para>This license places no restrictions on works that are
	  unrelated to the Work, nor does this license place any
	  restrictions on aggregating such works with the Work by any
	  means.</para>
      </listitem>
      <listitem>
	<para>Nothing in this license is intended to, or may be used
	  to, prevent complete compliance by all parties with all
	  applicable laws.</para>
      </listitem>
    </orderedlist>
  </sect1>
  <sect1 xml:id="LPPL:Warranty">
    <title>No Warranty</title>
    <para>There is no warranty for the Work.  Except when otherwise
      stated in writing, the Copyright Holder provides the Work
      <phrase>as is</phrase>, without warranty of any kind, either
      expressed or implied, including, but not limited to, the implied
      warranties of merchantability and fitness for a particular
      purpose.  The entire risk as to the quality and performance of
      the Work is with you.  Should the Work prove defective, you
      assume the cost of all necessary servicing, repair, or
      correction.</para>
    <para>In no event unless required by applicable law or agreed to
      in writing will The Copyright Holder, or any author named in the
      components of the Work, or any other party who may distribute
      and/or modify the Work as permitted above, be liable to you for
      damages, including any general, special, incidental or
      consequential damages arising out of any use of the Work or out
      of inability to use the Work (including, but not limited to,
      loss of data, data being rendered inaccurate, or losses
      sustained by anyone as a result of any failure of the Work to
      operate with any other programs), even if the Copyright Holder
      or said author or said other party has been advised of the
      possibility of such damages.</para>
  </sect1>
  <sect1 xml:id="LPPL:Maintenance">
    <title>Maintenance of The Work</title>
    <para>The Work has the status <phrase>author-maintained</phrase>
      if the Copyright Holder explicitly and prominently states near
      the primary copyright notice in the Work that the Work can only
      be maintained by the Copyright Holder or simply that it is
      <phrase>author-maintained</phrase>.</para>
    <para>The Work has the status <phrase>maintained</phrase> if there
      is a Current Maintainer who has indicated in the Work that they
      are willing to receive error reports for the Work (for example,
      by supplying a valid e-mail address). It is not required for the
      Current Maintainer to acknowledge or act upon these error
      reports.</para>
    <para>The Work changes from status <phrase>maintained</phrase> to
      <phrase>unmaintained</phrase> if there is no Current Maintainer,
      or the person stated to be Current Maintainer of the work cannot
      be reached through the indicated means of communication for a
      period of six months, and there are no other significant signs
      of active maintenance.</para>
    <para>You can become the Current Maintainer of the Work by
      agreement with any existing Current Maintainer to take over this
      role.</para>
    <para>If the Work is unmaintained, you can become the Current
      Maintainer of the Work through the following steps:</para>
    <orderedlist>
      <listitem>
	<para>Make a reasonable attempt to trace the Current
	  Maintainer (and the Copyright Holder, if the two differ)
	  through the means of an Internet or similar search.</para>
      </listitem>
      <listitem>
	<para>If this search is successful, then enquire whether the
	  Work is still maintained.</para>
	<orderedlist>
	  <listitem>
	    <para>If it is being maintained, then ask the Current
	      Maintainer to update their communication data within one
	      month.</para>
	  </listitem>
	  <listitem xml:id="LPPL:item:intention">
	    <para>If the search is unsuccessful or no action to resume
	      active maintenance is taken by the Current Maintainer,
	      then announce within the pertinent community your
	      intention to take over maintenance.  (If the Work is a
	      &LaTeX; work, this could be done, for example, by
	      posting to <uri type="news">comp.text.tex</uri>.)</para>
	  </listitem>
	</orderedlist>
      </listitem>
      <listitem>
	<orderedlist>
	  <listitem>
	    <para>If the Current Maintainer is reachable and agrees to
	      pass maintenance of the Work to you, then this takes
	      effect immediately upon announcement.</para>
	  </listitem>
	  <listitem xml:id="LPPL:item:announce">
	    <para>If the Current Maintainer is not reachable and the
	      Copyright Holder agrees that maintenance of the Work be
	      passed to you, then this takes effect immediately upon
	      announcement.</para>
	  </listitem>
	</orderedlist>
      </listitem>
      <listitem xml:id="LPPL:item:change">
	<para>If you make an <phrase>intention announcement</phrase>
	  as described in&nbsp;<xref
	    linkend="LPPL:item:intention"/> above and after three
	  months your intention is challenged neither by the Current
	  Maintainer nor by the Copyright Holder nor by other people,
	  then you may arrange for the Work to be changed so as to
	  name you as the (new) Current Maintainer.</para>
      </listitem>
      <listitem>
	<para>If the previously unreachable Current Maintainer becomes
	  reachable once more within three months of a change
	  completed under the terms of&nbsp;<xref
	    linkend="LPPL:item:announce"/>
	  or&nbsp;<xref linkend="LPPL:item:change"/>, then that
	  Current
	  Maintainer must become or remain the Current Maintainer upon
	  request provided they then update their communication data
	  within one month.</para>
      </listitem>
    </orderedlist>
    <para>A change in the Current Maintainer does not, of itself,
      alter the fact that the Work is distributed under the
      <acronym>LPPL</acronym> license.</para>
    <para>If you become the Current Maintainer of the Work, you should
      immediately provide, within the Work, a prominent and
      unambiguous statement of your status as Current Maintainer.  You
      should also announce your new status to the same pertinent
      community as in&nbsp;<xref linkend="LPPL:item:intention"/>
      above.</para>
  </sect1>
  <sect1 xml:id="LPPL:Distribute">
    <title>Whether and How to Distribute Works under This
      License</title>
    <para>This section contains important instructions, examples, and
      recommendations for authors who are considering distributing
      their works under this license.  These authors are addressed as
      <wordasword>you</wordasword> in this section.</para>
    <sect2 xml:id="LPPL:Choosing">
      <title>Choosing This License or Another License</title>
      <para>If for any part of your work you want or need to use
	<emphasis>distribution</emphasis> conditions that differ
	significantly from those in this license, then do not refer to
	this license anywhere in your work but, instead, distribute
	your work under a different license. You may use the text of
	this license as a model for your own license, but your license
	should not refer to the <acronym>LPPL</acronym> or otherwise
	give the impression that your work is distributed under the
	<acronym>LPPL</acronym>.</para>
      <para>The document <filename
	  xlink:type="tex">modguide</filename> in the base &LaTeX;
	distribution explains the motivation behind the conditions of
	this license.  It explains, for example, why distributing
	&LaTeX; under the <acronym>GNU</acronym> General Public
	License (<acronym>GPL</acronym>) was considered inappropriate.
	Even if your work is unrelated to &LaTeX;, the discussion in
	<filename xlink:type="tex">modguide</filename> may still be
	relevant, and authors intending to distribute their works
	under any license are encouraged to read it.</para>
    </sect2>
    <sect2 xml:id="LPPL:WithoutDistribution">
      <title>A Recommendation on Modification Without
	Distribution</title>
      <para>It is wise never to modify a component of the Work, even
	for your own personal use, without also meeting the above
	conditions for distributing the modified component.  While you
	might intend that such modifications will never be
	distributed, often this will happen by accident&mdash;you may
	forget that you have modified that component; or it may not
	occur to you when allowing others to access the modified
	version that you are thus distributing it and violating the
	conditions of this license in ways that could have legal
	implications and, worse, cause problems for the community. It
	is therefore usually in your best interest to keep your copy
	of the Work identical with the public one.  Many works provide
	ways to control the behavior of that work without altering any
	of its licensed components.</para>
    </sect2>
    <sect2 xml:id="LPPL:HowTo">
      <title>How to Use This License</title>
      <para>To use this license, place in each of the components of
	your work both an explicit copyright notice including your
	name and the year the work was authored and/or last
	substantially modified.  Include also a statement that the
	distribution and/or modification of that component is
	constrained by the conditions in this license.</para>
      <para>Here is an example of such a notice and statement:</para>
      <programlisting>
%%% pig.dtx
%%% Copyright 2005 M. Y. Name
%%
%% This work may be distributed and/or modified under the
%% conditions of the LaTeX Project Public License, either version 1.3
%% of this license or (at your option) any later version.
%% The latest version of this license is in
%%   http://www.latex-project.org/lppl.txt
%% and version 1.3 or later is part of all distributions of LaTeX
%% version 2005/12/01 or later.
%%
%% This work has the LPPL maintenance status `maintained'.
%% 
%% The Current Maintainer of this work is M. Y. Name.
%%
%% This work consists of the files pig.dtx and pig.ins
%% and the derived file pig.sty.
      </programlisting>
      <para>Given such a notice and statement in a file, the
	conditions given in this license document would apply, with
	the <wordasword>Work</wordasword> referring to the three files
	<filename xlink:type="dtx">pig</filename>, <filename
	  xlink:type="ins">pig</filename>, and <filename
	  xlink:type="sty">pig</filename> (the last being generated
	from <filename xlink:type="dtx">pig</filename> using <filename
	  xlink:type="ins">pig</filename>), the <phrase>Base
	  Interpreter</phrase> referring to any
	<phrase>&LaTeX;-Format</phrase>, and both <phrase>Copyright
	  Holder</phrase> and <phrase>Current Maintainer</phrase>
	referring to the person
	<personname>M.&nbsp;Y.&nbsp;Name</personname>.</para>
      <para>If you do not want the Maintenance section of
	<acronym>LPPL</acronym> to apply to your Work, change
	<wordasword>maintained</wordasword> above into
	<phrase>author-maintained</phrase>. However, we recommend that
	you use <wordasword>maintained</wordasword> as the Maintenance
	section was added in order to ensure that your Work remains
	useful to the community even when you can no longer maintain
	and support it yourself.</para>
    </sect2>
    <sect2 xml:id="LPPL:NotReplacements">
      <title>Derived Works That Are Not Replacements</title>
      <para>Several clauses of the <acronym>LPPL</acronym> specify
	means to provide reliability and stability for the user
	community. They therefore concern themselves with the case
	that a Derived Work is intended to be used as a (compatible or
	incompatible) replacement of the original Work. If this is not
	the case (e.g., if a few lines of code are reused for a
	completely different task), then clauses 6b and 6d shall not
	apply.</para>
    </sect2>
    <sect2 xml:id="LPPL:Recommendations">
      <title>Important Recommendations</title>
      <sect3>
	<title>Defining What Constitutes the Work</title>
	<para>The <acronym>LPPL</acronym> requires that distributions
	  of the Work contain all the files of the Work.  It is
	  therefore important that you provide a way for the licensee
	  to determine which files constitute the Work.  This could,
	  for example, be achieved by explicitly listing all the files
	  of the Work near the copyright notice of each file or by
	  using a line such as:</para>
	<programlisting>
%% This work consists of all files listed in manifest.txt.
	</programlisting>
	<para>in that place.  In the absence of an unequivocal list it
	  might be impossible for the licensee to determine what is
	  considered by you to comprise the Work and, in such a case,
	  the licensee would be entitled to make reasonable
	  conjectures as to which files comprise the Work.</para>
      </sect3>
    </sect2>
  </sect1>
</chapter>
