Copyright (C) 2007-2025 Free Software Foundation, Inc.
See the end of the file for license conditions.


NOTES ON COPYRIGHTS AND LICENSES

Some terminology:

A "copyright notice" consists of one or a few lines of this format:
"Copyright (C) 2007-2025 Free Software Foundation, Inc."

A "license notice" is a statement of permissions, and is usually much
longer, eg the text "GNU Emacs is free software...".


Summary for the impatient:

1. Don't add code to Emacs written by someone other than yourself
without thinking about the legal aspect.  Even if the changes are
trivial, consider if they combine with previous changes by the same
author to make a non-trivial total.  If so, make sure they have an
assignment.  If adding a whole file adjust the copyright statements in
the file.

2. When installing code written by someone else, the commit
should be in the name of the author of the code, not the person who
installs it.  Also use commit's "--author" option.
Do not install any of your own changes in the same commit.

3. With images, add the legal info to a README file in the directory
containing the image.

4. If you add a lot of text to a previously trivial file that had no
legal notices, consider if you should add a copyright statement.

5. Please don't just add an FSF copyright without checking that is the
right thing to do.


Every non-trivial file distributed through the Emacs repository should be
self-explanatory in terms of copyright and license.  This includes
files that are not distributed in Emacs releases (for example, the
admin/ directory), because the whole Emacs repository is publicly
available.

The definition of triviality is a little vague, but a rule of thumb is
that any file with less than 15 lines of actual content is trivial.  If
a file is auto-generated (eg ldefs-boot.el) from another one in the
repository, then it does not really matter about adding a copyright
statement to the generated file.

Legal advice says that we could, if we wished, put a license notice
even in trivial files, because copyright law in general looks at the
overall work as a whole.  It is not _necessary_ to do so, and rms
prefers that we do not.  This means one needs to take care that trivial
files do not grow and become non-trivial without having a license
added.  NB consequently, if you add a lot of text to a small file,
consider whether your changes have made the file worthy of a copyright
notice, and if so, please add one.

It can be helpful to put a reminder comment at the start of a trivial
file, eg: "add a license notice if this grows to > 10 lines of code".

The years in the copyright notice should be updated every year (see
file "years" in this directory).  The PDF versions of refcards etc
should display copyright notices (an exception to the rule about
"generated" files), but these can just display the latest year.  The
full list of years should be kept in comments in the source file.  If
these are distributed in the repository, check in a regenerated
version when the tex files are updated.

Copyright changes should be propagated to any associated repositories
(eg Gnus, MH-E), but I think in every case this happens automatically
(?).

All README (and other such text files) that are non-trivial should
contain copyright statements and GPL license notices, exactly as .el
files do (see e.g. README in the top-level directory).  Before 2007,
we used a simple, short statement permitting copying and modification
provided legal notices were retained.  In Feb 2007 we switched to the
standard GPL text, on legal advice.  Some older text files in etc/
should, however, keep their current licenses (see below for list).

For image files, the copyright and license details should be recorded
in a README file in each directory with images. (Legal advice says
that we need not add notices to each image file individually, if they
allow for that.).  It is recommended to use the word "convert" to
describe the automatic process of changing an image from one format to
another (https://lists.gnu.org/r/emacs-devel/2007-02/msg00618.html).


When installing a file with an "unusual" license (after checking first
it is ok), put a copy of the copyright and license in the file (if
possible.  It's ok if this makes the file incompatible with its
original format, if it can still be used by Emacs), or in a README
file in the relevant directory.

The vast majority of files are copyright FSF and distributed under the
GPL.  A few files (mainly related to language and charset support) are
copyright AIST alone, or both AIST and FSF. (Contact Kenichi Handa
with questions about legal issues in such files.) In all these cases,
the copyright years in each file should be updated each year.

There are some exceptions to the points in the previous paragraph, and
these are listed below for reference, together with any files where
the copyright needs to be updated in "unusual" ways.

If you find any other such cases, please consult to check they are ok,
and note them in this file.  This includes missing copyright notices,
and "odd" copyright holders.  In most cases, individual authors should
not appear in copyright statements.  Either the copyright has been
assigned (check copyright.list) to the FSF (in which case the original
author should be removed and the year(s) transferred to the FSF); or
else it is possible the file should not be in Emacs at all (please
report!).

Note that it seems painfully clear that one cannot rely on commit logs,
or even change log entries, for older changes.  People often installed
changes from others, without recording the true authorship.

[For reference, most of these points were established via email with
rms, 2007/1, "Copyright years".

In March 2011, information on some files no longer included was removed.
Consult older versions of this document if interested.]


lisp/version.el           # emacs-copyright
lib-src/ebrowse.c         # version
lib-src/etags.c           # print_version
lib-src/rcs2log           # Copyright
Cocoa/Emacs.base/Contents/Info.plist
Cocoa/Emacs.base/Contents/Resources/English.lproj/InfoPlist.strings
GNUstep/Emacs.base/Resources/Info-gnustep.plist
   'set-copyright' in admin.el will do all the above.

aclocal.m4
configure
m4/*.m4
 - These files are copyright FSF, with unlimited permission to copy,
   distribute and modify, so long as the copyright notice is preserved.
   Exception: m4/pkg.m4 is copyright Scott James Remnant; it is
   distributed under the same terms as for the rest of Emacs.

lib/Makefile.in
 - copyright FSF, with MIT-like license

build-aux/install-sh
 - this file is copyright MIT, which is OK.  Leave the copyright alone.

etc/refcards/*.tex
  also update the \def\year macro for the latest year.

etc/future-bug
 - doesn't need a humorless disclaimer, because Karl Fogel says we
 can consider it part of Emacs, and he has a blanker disclaimer for
 Emacs changes. (email to rgm "[Emacs-commit] emacs/etc future-bug",
 2007028)

etc/letter.pbm,letter.xpm
  - trivial, no notice needed.
<https://lists.gnu.org/r/emacs-devel/2007-02/msg00324.html>

etc/HELLO
  standard notices.  Just a note that although the file itself is not
  really copyrightable, in the wider context of it being part of
  Emacs (and written by those with assignments), a standard notice is
  fine.

etc/MAILINGLISTS
  rms: simple license is fine for this file

leim/CXTERM-DIC/4Corner.tit, ARRAY30.tit, CCDOSPY.tit, ECDICT.tit,
ETZY.tit, PY-b5.tit, Punct-b5.tit, Punct.tit, QJ-b5.tit, QJ.tit,
SW.tit, TONEPY.tit, ZOZY.tit
  - leave the copyrights alone.

leim/MISC-DIC/CTLau-b5.html, CTLau.html, cangjie-table.b5, cangjie-table.cns,
pinyin.map, ziranma.cin
  - leave the copyright alone.
Note that pinyin.map, ziranma.cin (and hence the generated
leim/quail/PY.el, ZIRANMA.el) are under GPLv1 or later.

leim/SKK-DIC/SKK-JISYO.L
ja-dic/ja-dic.el
  (the latter is auto-generated from the former).  Leave the copyright alone.

lib-src/etags.c
  Copyright information is duplicated in etc/ETAGS.README.  Update that
  file too.

  Until 2007 etags.c was described as being copyright FSF and Ken Arnold.
  After some investigation in Feb 2007, then to the best of our
  knowledge we believe that the original 1984 Emacs version was based
  on the version in BSD4.2.  See for example this 1985 post from Ken Arnold:
  <https://groups.google.com/group/mod.sources/browse_thread/thread/ffe5c55845a640a9>
    I have received enough requests for the current source to ctags
    to post it.  Here is the latest version (what will go out with
    4.3, modulo any bugs fixed during the beta period).  It is the
    4.2 ctags with recognition of yacc and lex tags added.

  See also a 1984 version of ctags (no copyright) posted to net.sources:
  <https://groups.google.com/group/net.sources/msg/a21b6c21be12a98d>
  Version of etags.c in emacs-16.56 duplicates comment typos.

  Accordingly, in Feb 2007 we added a 1984 copyright for the
  University of California and a revised BSD license.  The terms of
  this require that the full license details be available in binary
  distributions - hence the file etc/ETAGS.README.  The fact that the
  --version output just says "Copyright <year> FSF" is apparently OK
  from a legal point of view.

lisp/cedet/semantic/imenu.el
  - See https://lists.gnu.org/r/emacs-devel/2010-03/msg00410.html
   in which Eric Ludlam established that the remaining contributions
   from authors other than himself were negligible.

lisp/play/tetris.el
  - no special rules about the copyright.  We note here that we believe
  (2007/1) there is no problem with our use of the name "tetris" or
  the concept.
  rms: "My understanding is that game rules as such are not copyrightable."
  <https://lists.gnu.org/r/emacs-devel/2007-01/msg00960.html>
  rms: Legal advice is that we are ok and need not worry about this.


lisp/net/tramp.el
  - there are also copyrights in the body of the file.  Update these too.


lwlib/
rms (2007/02/17): "lwlib is not assigned to the FSF; we don't consider
it part of Emacs. [...] Therefore non-FSF copyrights are ok in lwlib."

NB don't change the GPL version used for lwlib .c and .h files (see
below).

FSF copyrights should only appear in files which have undergone
non-trivial cumulative changes from the original versions in the Lucid
Widget Library.  NB this means that if you make non-trivial changes to
a file with no FSF copyright, you should add one.  Also, if changes are
reverted to the extent that a file becomes basically the same as the
original version, the FSF copyright should be removed.

In my (rgm) opinion, as of Feb 2007, all the non-trivial files differ
significantly from the original versions, with the exception of
lwlib-Xm.h.  Most of the changes that were made to this file have
subsequently been reverted.  Therefore I removed the FSF copyright from
this file (which is arguably too trivial to merit a notice anyway).  I
added FSF copyright to the following files which did not have them
already: Makefile.in, lwlib-Xaw.c, lwlib-int.h (borderline),
lwlib-utils.c (borderline), lwlib.c, lwlib.h.

Copyright years before the advent of public CVS in 2001 were those
when I judged (from the CVS logs) that non-trivial amounts of change
had taken place.  I also adjusted the existing FSF years in xlwmenu.c,
xlwmenu.h, and xlwmenuP.h on the same basis.

Note that until Feb 2007, the following files in lwlib were lacking
notices: lwlib-int.h, lwlib.h, lwlib-Xaw.h, lwlib-Xlw.h, lwlib-utils.h

The following files did not list a Lucid copyright: xlwmenu.h,
xlwmenuP.h.

To the best of our knowledge, all the code files in lwlib were
originally part of the Lucid Widget Library, even if they did not say
so explicitly.  For example, they were all present in Lucid Emacs 19.1
in 1992.  The exceptions are the two Xaw files, which did not appear
till Lucid Emacs 19.9 in 1994.  The file lwlib-Xaw.h is too trivial to
merit a copyright notice, but would presumably have the same one as
lwlib-Xaw.c.  We have been unable to find a true standalone version of
LWL, if there was such a thing, to check definitively.

To clarify the situation, in Feb 2007 we added Lucid copyrights and
GPL notices to those files lacking either that were non-trivial,
namely: lwlib-int.h, lwlib.h, xlwmenu.h, xlwmenuP.h.  This represents
our best understanding of the legal status of these files.  We also
clarified the notices in Makefile.in, which was originally the
Makefile auto-generated from Lucid's Imakefile.

As of Feb 2007, the following files are considered too trivial for
notices: lwlib-Xaw.h, lwlib-Xlw.h, lwlib-utils.h.

The version of lwlib/ first installed in Emacs seems to be the same as
that used in Lucid Emacs 19.8 (released 6-sep-93); except the two Xaw
files, which did not appear till Athena support was added in Lucid
Emacs 19.9.  In Lucid Emacs 19.1, all files were under GPLv1 or later,
but by Lucid Emacs 19.8, lwlib.c and xlwmenu.c had been switched to v2
or later.  These are the versions that were first installed in Emacs.
So in GNU Emacs, these two files have been under v2 or later since
1994.

It seems that it was the intention of Lucid to use v1 or later
(excepting the two files mentioned previously); so this is the license
we have used when adding notices to code that did not have notices
originally.  Although we have the legal right to switch to v2 or later,
rms prefers that we do not do so.


doc/*/doclicense.texi
  - leave the copyright alone in this imported file.

doc/*/*.texi - All manuals should be under GFDL (but see below), and
should include a copy of it, so that they can be distributed
separately.  efaq.texi has a different license, for some reason no-one
can remember.
https://lists.gnu.org/r/emacs-devel/2007-04/msg00583.html
https://lists.gnu.org/r/emacs-devel/2007-04/msg00618.html

doc/misc/mh-e.texi is dual-licensed (GPL and GFDL) per agreement with
FSF (reconfirmed by rms Aug 25 2008).  Discussion with
licensing@fsf.org starting on Thu, 07 Aug 2003 with subject:
"[gnu.org #58812] Changing license of MH-E manual"


msdos/sed*.inp - These files are copyright FSF and distributed under
an MIT-like license.


oldXMenu/
  Keep the "copyright.h" method used by X11, rather than moving the
  licenses into the files.  Note that the original X10.h did not use
  copyright.h, but had an explicit notice, which we retain.

If you make non-trivial changes to a file which does not have an FSF
notice, add one and a GPL notice (as per Activate.c).  If changes to a
file are reverted such that it becomes essentially the same as the
original X11 version, remove the FSF notice and GPL.

Only the files which differ significantly from the original X11
versions should have FSF copyright and GPL notices.  At time of writing
(Feb 2007), this is: Activate.c, Create.c, Internal.c.  I (rgm)
established this by diff'ing the current files against those in X11R1,
and when I found significant differences looking in the ChangeLog for
the years they originated (the CVS logs are truncated before 1999).  I
therefore removed the FSF notices (added in 200x) from the other
files.  There are some borderline cases IMO: AddSel.c, InsSel.c,
XMakeAssoc.c, XMenu.h.  For these I erred on the side of NOT adding FSF
notices.

With regards to whether the files we have changed should have GPL
added or not, rms says (2007-02-25, "oldXmenu issues"):

    It does not make much difference, because oldXmenu is obsolete
    except for use in Emacs (and it is not normally used in Emacs any
    more either).

    So, to make things simple, please put our changes under the GPL.

insque.c had no copyright notice until 2005.  The version of insque.c
added to Emacs 1992-01-27 is essentially the same as insremque.c added
to glic three days later by Roland McGrath, with an FSF copyright and
GPL, but no ChangeLog entry.
To the best of his recollection, McGrath (who has a copyright
assignment) was the author of this file (email from roland at frob.com
to rms, 2007-02-23, "Where did insque.c come from?").  The FSF
copyright and GPL in this file are therefore correct as far as we
understand it.

Imakefile had no legal info in Feb 2007, but was obviously based on
the X11 version (which also had no explicit legal info).  As it was
unused, I removed it.  It would have the same MIT copyright as
Makefile.in does now.


src/gmalloc.c
  - contains numerous copyrights from the GNU C library.  Leave them alone.

nt/inc/dirent.h
  - see comments below.  This file is OK to be released with Emacs
  22, but we may want to revisit it afterwards.


** Some notes on resolved issues, for historical information only

etc/TERMS
rms: "surely written either by me or by ESR.  (If you can figure out
which year, I can probably tell you which.)  Either way, we have papers
for it."  It was present in Emacs-16.56 (15-jul-85).  rms: "Then I
conclude it was written by me."

lisp/term/README
  - had no copyright notice till Feb 2007.  ChangeLog.3 suggests it was
  written by Eric S. Raymond.  When asked by rms on 14 Feb 2007 he said:

    I don't remember writing it, but it reads like my prose and I believe
    I wrote the feature(s) it's describing.  So I would have been the
    likeliest person to write it.

    Odds are that I did, but I'm not certain.

  Accordingly, FSF copyright was added.

src/unexhp9k800.c
  https://lists.gnu.org/r/emacs-devel/2007-02/msg00138.html
  - briefly removed due to legal uncertainly Jan-Mar 2007.  The
  relevant assignment is under "hp9k800" in copyright.list.  File was
  written by John V. Morris at HP, and disclaimed by the author and
  HP.  So this file is public domain.


lisp/progmodes/python.el
Dave Love alerted us to a potential legal problem:
https://lists.gnu.org/r/emacs-pretest-bug/2007-04/msg00459.html

On consultation with a lawyer, we found there was no problem:
https://lists.gnu.org/r/emacs-devel/2007-05/msg00466.html


** Issues that are "fixed" for the release of Emacs 22, but we may
   wish to revisit later in more detail


admin/check-doc-strings
  File says it's in the public domain, but that might not make it so.

etc/e/eterm-color.ti
nt/inc/dirent.h
  On legal advice from Matt Norwood, the following comment was added
  to these files in Feb/Mar 2007:

    The code here is forced by the interface, and is not subject to
    copyright, constituting the only possible expression of the
    algorithm in this format.

  With the addition of this notice, these files are OK for the
  upcoming Emacs-22 release.  Post-release, we can revisit this issue
  and possibly add a list of all authors who have changed these files.
  (details in email from Matt Norwood to rms, 2007/02/03).

src/s/aix3-2.h, hpux8.h, hpux9.h, irix5-0.h, netbsd.h, usg5-4-2.h
  [note some of these have since been merged into other files]
  - all these (not obviously trivial) files were missing copyrights
  till Feb 2007, when FSF copyright was added.  Matt Norwood advised:

    For now, I think the best policy is to assume that we do have
    assignments from the authors (I recall many of these header files
    as having been originally written by rms), and to attach an FSF
    copyright with GPL notice.  We can amend this if and when we
    complete the code audit.  Any additions to these files by
    non-assigned authors are arguably "de minimis" contributions to
    Emacs: small changes or suggestions to a work that are subsumed in
    the main authors' copyright in the entire work.

Here is my (rgm) take on the details of the above files:

? irix5-0.h
  I would say started non-trivial (1993, jimb, heavily based
  on irix4-0.h).  A few borderline non-tiny changes since.

usg5-4-2.h
 started non-trivial, but was heavily based on usg5-4.h, which was and is
 copyright FSF.  only tiny changes since installed.

aix3-2.h, hpux8.h, hpux9.h, netbsd.h
  started trivial, grown in tiny changes.

netbsd.h:
Roland McGrath said to rms (2007/02/17): "I don't really remember
anything about it.  If I put it in without other comment, then probably
I wrote it myself."


Someone might want to tweak the copyright years (for dates before
2001) that I used in all these files.

Note: erring on the side of caution, I also added notices to some
files I thought might be considered non-trivial (if one includes
comment) in s/:
  aix4-1.h hpux10.h irix6-5.h
  sol2.h

(everything with > 30 non-blank lines, which at least is _some_ kind of
system)


*** These are copyright issues that need not be fixed until after
    Emacs 22 is released (though if they can be fixed before, that is
    obviously good):


Is it OK to just remove a file for legal reasons, or is something more
drastic (excision from the entire repository history) needed? A
removed file is still available from the repository, if suitable
options are applied. (This issue obviously does not affect a release).
  rms: will ask lawyer


Make sure that all files with non-standard copyrights or licenses are
noted in this file.


REMOVED etc/gnu.xpm, nt/icons/emacs21.ico, nt/icons/sink.ico
  - Restore if find legal info.  emacs21.ico is not due to Davenport.
  Geoff Voelker checked but could not find a record of where it came
  from.


etc/images
  Image files from GTK, Gnome are under GPLv2 (no "or later"?).  RMS will
  contact image authors in regards to future switch to v3.


etc/TUTORIAL* (translations)
  switch to GPL (see english TUTORIAL)
  rms: "We can leave the TUTORIAL translations alone until their
  maintainers update them."
  Can adapt short license text from end of GPL translations at:
  https://www.gnu.org/licenses/translations.html
  Only a few sentences around the license notice need changing from
  previous version.
Done: TUTORIAL.eo


*** These are copyright issues still to be addressed:

None known.


** NOTES ON RELICENSING TO GPL3

The EMACS_22_BASE branch was changed to GPLv3 (or later) 2007/07/25.

Some notes:
(see https://lists.gnu.org/r/emacs-devel/2007-07/msg01431.html)

1. There are some files in the Emacs tree which are not part of Emacs (eg
those included from Gnulib).  These are all copyright FSF and (at time
of writing) GPL >= 2.  rms says may as well leave the licenses of these
alone (may import them from Gnulib again).  These are:

    Gnulib:
    build-aux/config.guess
    build-aux/config.sub
    build-aux/move-if-change
    doc/man/texinfo.tex
    lib/*.[ch]
    lib/gnulib.mk.in
    src/gmalloc.c
    src/termcap.c
    src/tparam.c

Note _not_ included in the above are src/regex.{c,h} (rms: "That
forked version is only in Emacs, so definitely relicense that."), and
oldXMenu/insque.c (rms: "We wrote that specifically for Emacs, so
definitely relicense that.").

2. The files that are copyright FSF and AIST, or AIST alone, should be
and were updated, ditto the oldXMenu files with FSF copyright.

3. lwlib/

Files originally in Lucid Widget Library were left alone (excludes
ChangeLog, etc), ie remain under GPL v1 or later, or v2 or later.
(rms: "We may as well leave this alone, since we are never going to
change it much.")

4. There are some files where the FSF holds no copyright.  These were
left alone:

   leim/MISC-DIC/CTLau-b5.html  >= v2
   leim/MISC-DIC/CTLau.html     >= v2
     (above included in lisp/international/titdic-cnv.el)
   leim/MISC-DIC/pinyin.map     >= v1
   leim/MISC-DIC/ziranma.cin    >= v1
   leim/SKK-DIC/SKK-JISYO.L     >= v2
   leim/SKK-DIC/README          >= v2
   leim/ja-dic/ja-dic.el        >= v2

5. At time of writing, some non-Emacs icons included from Gnome remain
under GPLv2 (no "or later").  See:

   etc/images/gnus/README
   etc/images/mail/README
   etc/images/README
   nt/icons/README


This file is part of GNU Emacs.

GNU Emacs is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
