Python Licenses

PYTHON 3.14.4 - LEGAL NOTICE AND THIRD-PARTY LICENSES

Generated from source tree: /Users/anarnold/Downloads/Python-3.14.4

Generated on: 2026-04-20

This document consolidates public license texts and copyright notices

present in this CPython source release for Python itself and incorporated

third-party software.

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1) PYTHON COPYRIGHT NOTICE

======================================================================

Source: Doc/copyright.rst

*********

Python and this documentation is:

reserved.

-------

See :ref:`history-and-license` for complete license and permissions information.

======================================================================

2) PYTHON CORE LICENSE TERMS

======================================================================

Source: LICENSE

A. HISTORY OF THE SOFTWARE

==========================

Python was created in the early 1990s by Guido van Rossum at Stichting

Mathematisch Centrum (CWI, see https://www.cwi.nl) in the Netherlands

as a successor of a language called ABC. Guido remains Python's

principal author, although it includes many contributions from others.

In 1995, Guido continued his work on Python at the Corporation for

National Research Initiatives (CNRI, see https://www.cnri.reston.va.us)

in Reston, Virginia where he released several versions of the

software.

In May 2000, Guido and the Python core development team moved to

BeOpen.com to form the BeOpen PythonLabs team. In October of the same

year, the PythonLabs team moved to Digital Creations, which became

Zope Corporation. In 2001, the Python Software Foundation (PSF, see

https://www.python.org/psf/) was formed, a non-profit organization

created specifically to own Python-related Intellectual Property.

Zope Corporation was a sponsoring member of the PSF.

All Python releases are Open Source (see https://opensource.org for

the Open Source Definition). Historically, most, but not all, Python

releases have also been GPL-compatible; the table below summarizes

the various releases.

Release Derived Year Owner GPL-

from compatible? (1)

0.9.0 thru 1.2 1991-1995 CWI yes

1.3 thru 1.5.2 1.2 1995-1999 CNRI yes

1.6 1.5.2 2000 CNRI no

2.0 1.6 2000 BeOpen.com no

1.6.1 1.6 2001 CNRI yes (2)

2.1 2.0+1.6.1 2001 PSF no

2.0.1 2.0+1.6.1 2001 PSF yes

2.1.1 2.1+2.0.1 2001 PSF yes

2.1.2 2.1.1 2002 PSF yes

2.1.3 2.1.2 2002 PSF yes

2.2 and above 2.1.1 2001-now PSF yes

Footnotes:

(1) GPL-compatible doesn't mean that we're distributing Python under

the GPL. All Python licenses, unlike the GPL, let you distribute

a modified version without making your changes open source. The

GPL-compatible licenses make it possible to combine Python with

other software that is released under the GPL; the others don't.

(2) According to Richard Stallman, 1.6.1 is not GPL-compatible,

because its license has a choice of law clause. According to

CNRI, however, Stallman's lawyer has told CNRI's lawyer that 1.6.1

is "not incompatible" with the GPL.

Thanks to the many outside volunteers who have worked under Guido's

direction to make these releases possible.

B. TERMS AND CONDITIONS FOR ACCESSING OR OTHERWISE USING PYTHON

===============================================================

Python software and documentation are licensed under the

Python Software Foundation License Version 2.

Starting with Python 3.8.6, examples, recipes, and other code in

the documentation are dual licensed under the PSF License Version 2

and the Zero-Clause BSD license.

Some software incorporated into Python is under different licenses.

The licenses are listed with code falling under that license.

PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2

--------------------------------------------

Python Software Foundation License, Version 2

======================================================================

3) INCORPORATED THIRD-PARTY SOFTWARE LICENSES AND ACKNOWLEDGEMENTS

======================================================================

Source: Doc/license.rst (section: Licenses and Acknowledgements for Incorporated Software)

.. _OtherLicenses:

Licenses and Acknowledgements for Incorporated Software

=======================================================

This section is an incomplete, but growing list of licenses and acknowledgements

for third-party software incorporated in the Python distribution.

Mersenne Twister

----------------

The :mod:`!_random` C extension underlying the :mod:`random` module

includes code based on a download from

http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/emt19937ar.html. The following are

the verbatim comments from the original code::

A C-program for MT19937, with initialization improved 2002/1/26.

Coded by Takuji Nishimura and Makoto Matsumoto.

Before using, initialize the state by using init_genrand(seed)

or init_by_array(init_key, key_length).

BSD 3-Clause License

Any feedback is very welcome.

http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html

email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)

Sockets

-------

The :mod:`socket` module uses the functions, :c:func:`!getaddrinfo`, and

:c:func:`!getnameinfo`, which are coded in separate source files from the WIDE

Project, https://www.wide.ad.jp/. ::

BSD 3-Clause License

Asynchronous socket services

----------------------------

The :mod:`!test.support.asynchat` and :mod:`!test.support.asyncore`

modules contain the following notice::

Permission to use, copy, modify, and distribute this software and

its documentation for any purpose and without fee is hereby

granted, provided that the above copyright notice appear in all

copies and that both that copyright notice and this permission

notice appear in supporting documentation, and that the name of Sam

Rushing not be used in advertising or publicity pertaining to

distribution of the software without specific, written prior

permission.

SAM RUSHING DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,

INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN

NO EVENT SHALL SAM RUSHING BE LIABLE FOR ANY SPECIAL, INDIRECT OR

CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS

OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,

NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN

CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

Cookie management

-----------------

The :mod:`http.cookies` module contains the following notice::

Permission to use, copy, modify, and distribute this software

and its documentation for any purpose and without fee is hereby

granted, provided that the above copyright notice appear in all

copies and that both that copyright notice and this permission

notice appear in supporting documentation, and that the name of

Timothy O'Malley not be used in advertising or publicity

pertaining to distribution of the software without specific, written

prior permission.

Timothy O'Malley DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS

SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY

AND FITNESS, IN NO EVENT SHALL Timothy O'Malley BE LIABLE FOR

ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,

WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS

ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR

PERFORMANCE OF THIS SOFTWARE.

Execution tracing

-----------------

The :mod:`trace` module contains the following notice::

err... reserved and offered to the public under the terms of the

Python 2.2 license.

Author: Zooko O'Whielacronx

http://zooko.com/

mailto:zooko@zooko.com

Author: Skip Montanaro

Author: Andrew Dalke

Author: Skip Montanaro

Permission to use, copy, modify, and distribute this Python software and

its associated documentation for any purpose without fee is hereby

granted, provided that the above copyright notice appears in all copies,

and that both that copyright notice and this permission notice appear in

supporting documentation, and that the name of neither Automatrix,

Bioreason or Mojam Media be used in advertising or publicity pertaining to

distribution of the software without specific, written prior permission.

UUencode and UUdecode functions

-------------------------------

The ``uu`` codec contains the following notice::

Cathedral City, California Republic, United States of America.

Permission to use, copy, modify, and distribute this software and its

documentation for any purpose and without fee is hereby granted,

provided that the above copyright notice appear in all copies and that

both that copyright notice and this permission notice appear in

supporting documentation, and that the name of Lance Ellinghouse

not be used in advertising or publicity pertaining to distribution

of the software without specific, written prior permission.

LANCE ELLINGHOUSE DISCLAIMS ALL WARRANTIES WITH REGARD TO

THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND

FITNESS, IN NO EVENT SHALL LANCE ELLINGHOUSE CENTRUM BE LIABLE

FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT

OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

Modified by Jack Jansen, CWI, July 1995:

- Use binascii module to do the actual line-by-line conversion

between ascii and binary. This results in a 1000-fold speedup. The C

version is still 5 times faster, though.

- Arguments more compliant with Python standard

XML Remote Procedure Calls

--------------------------

The :mod:`xmlrpc.client` module contains the following notice::

The XML-RPC client interface is

By obtaining, using, and/or copying this software and/or its

associated documentation, you agree that you have read, understood,

and will comply with the following terms and conditions:

Permission to use, copy, modify, and distribute this software and

its associated documentation for any purpose and without fee is

hereby granted, provided that the above copyright notice appears in

all copies, and that both that copyright notice and this permission

notice appear in supporting documentation, and that the name of

Secret Labs AB or the author not be used in advertising or publicity

pertaining to distribution of the software without specific, written

prior permission.

SECRET LABS AB AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD

TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANT-

ABILITY AND FITNESS. IN NO EVENT SHALL SECRET LABS AB OR THE AUTHOR

BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY

DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,

WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS

ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE

OF THIS SOFTWARE.

test_epoll

----------

The :mod:`!test.test_epoll` module contains the following notice::

MIT License

Select kqueue

-------------

The :mod:`select` module contains the following notice for the kqueue

interface::

BSD 2-Clause License

SipHash24

---------

The file :file:`Python/pyhash.c` contains Marek Majkowski' implementation of

Dan Bernstein's SipHash24 algorithm. It contains the following note::

Permission is hereby granted, free of charge, to any person obtaining a copy

of this software and associated documentation files (the "Software"), to deal

in the Software without restriction, including without limitation the rights

to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

copies of the Software, and to permit persons to whom the Software is

furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in

all copies or substantial portions of the Software.

</MIT License>

Original location:

https://github.com/majek/csiphash/

Solution inspired by code from:

Samuel Neves (supercop/crypto_auth/siphash24/little)

djb (supercop/crypto_auth/siphash24/little2)

Jean-Philippe Aumasson (https://131002.net/siphash/siphash24.c)

strtod and dtoa

---------------

The file :file:`Python/dtoa.c`, which supplies C functions dtoa and

strtod for conversion of C doubles to and from strings, is derived

from the file of the same name by David M. Gay, currently available

from https://web.archive.org/web/20220517033456/http://www.netlib.org/fp/dtoa.c.

The original file, as retrieved on March 16, 2009, contains the following

/****************************************************************

* The author of this software is David M. Gay.

David M. Gay dtoa License

***************************************************************/