Python Licenses

From Doc/license.rst

*******************

History and License

*******************

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 (now Zope Corporation; see

https://www.zope.org/). 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 is 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.

+----------------+--------------+------------+------------+-----------------+

+================+==============+============+============+=================+

| 0.9.0 thru 1.2 | n/a | 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 | no |

+----------------+--------------+------------+------------+-----------------+

| 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 |

+----------------+--------------+------------+------------+-----------------+

.. note::

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.

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

make these releases possible.

Terms and conditions for accessing or otherwise using Python

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

Python software and documentation are licensed under the

:ref:`PSF License Agreement <PSF-license>`.

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

the documentation are dual licensed under the PSF License Agreement

and the :ref:`Zero-Clause BSD license <BSD0>`.

Some software incorporated into Python is under different licenses.

The licenses are listed with code falling under that license.

See :ref:`OtherLicenses` for an incomplete list of these licenses.

.. _PSF-license:

PSF LICENSE AGREEMENT FOR PYTHON |release|

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

.. parsed-literal::

1. This LICENSE AGREEMENT is between the Python Software Foundation ("PSF"), and

the Individual or Organization ("Licensee") accessing and otherwise using Python

|release| software in source or binary form and its associated documentation.

2. Subject to the terms and conditions of this License Agreement, PSF hereby

grants Licensee a nonexclusive, royalty-free, world-wide license to reproduce,

analyze, test, perform and/or display publicly, prepare derivative works,

distribute, and otherwise use Python |release| alone or in any derivative

version, provided, however, that PSF's License Agreement and PSF's notice of

Reserved" are retained in Python |release| alone or in any derivative version

prepared by Licensee.

3. In the event Licensee prepares a derivative work that is based on or

incorporates Python |release| or any part thereof, and wants to make the

derivative work available to others as provided herein, then Licensee hereby

agrees to include in any such work a brief summary of the changes made to Python

|release|.

4. PSF is making Python |release| available to Licensee on an "AS IS" basis.

PSF MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED. BY WAY OF

EXAMPLE, BUT NOT LIMITATION, PSF MAKES NO AND DISCLAIMS ANY REPRESENTATION OR

WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT THE

USE OF PYTHON |release| WILL NOT INFRINGE ANY THIRD PARTY RIGHTS.

5. PSF SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON |release|

FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS A RESULT OF

MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON |release|, OR ANY DERIVATIVE

THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.

6. This License Agreement will automatically terminate upon a material breach of

its terms and conditions.

7. Nothing in this License Agreement shall be deemed to create any relationship

of agency, partnership, or joint venture between PSF and Licensee. This License

Agreement does not grant permission to use PSF trademarks or trade name in a

trademark sense to endorse or promote products or services of Licensee, or any

third party.

8. By copying, installing or otherwise using Python |release|, Licensee agrees

to be bound by the terms and conditions of this License Agreement.

BEOPEN.COM LICENSE AGREEMENT FOR PYTHON 2.0

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

BEOPEN PYTHON OPEN SOURCE LICENSE AGREEMENT VERSION 1

.. parsed-literal::

1. This LICENSE AGREEMENT is between BeOpen.com ("BeOpen"), having an office at

160 Saratoga Avenue, Santa Clara, CA 95051, and the Individual or Organization

("Licensee") accessing and otherwise using this software in source or binary

form and its associated documentation ("the Software").

2. Subject to the terms and conditions of this BeOpen Python License Agreement,

BeOpen hereby grants Licensee a non-exclusive, royalty-free, world-wide license

to reproduce, analyze, test, perform and/or display publicly, prepare derivative

works, distribute, and otherwise use the Software alone or in any derivative

version, provided, however, that the BeOpen Python License is retained in the

Software, alone or in any derivative version prepared by Licensee.

3. BeOpen is making the Software available to Licensee on an "AS IS" basis.

BEOPEN MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED. BY WAY OF

EXAMPLE, BUT NOT LIMITATION, BEOPEN MAKES NO AND DISCLAIMS ANY REPRESENTATION OR

WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT THE

USE OF THE SOFTWARE WILL NOT INFRINGE ANY THIRD PARTY RIGHTS.

4. BEOPEN SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF THE SOFTWARE FOR

ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS A RESULT OF USING,

MODIFYING OR DISTRIBUTING THE SOFTWARE, OR ANY DERIVATIVE THEREOF, EVEN IF

ADVISED OF THE POSSIBILITY THEREOF.

5. This License Agreement will automatically terminate upon a material breach of

its terms and conditions.

6. This License Agreement shall be governed by and interpreted in all respects

by the law of the State of California, excluding conflict of law provisions.

Nothing in this License Agreement shall be deemed to create any relationship of

agency, partnership, or joint venture between BeOpen and Licensee. This License

Agreement does not grant permission to use BeOpen trademarks or trade names in a

trademark sense to endorse or promote products or services of Licensee, or any

third party. As an exception, the "BeOpen Python" logos available at

http://www.pythonlabs.com/logos.html may be used according to the permissions

granted on that web page.

7. By copying, installing or otherwise using the software, Licensee agrees to be

bound by the terms and conditions of this License Agreement.

CNRI LICENSE AGREEMENT FOR PYTHON 1.6.1

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

.. parsed-literal::

1. This LICENSE AGREEMENT is between the Corporation for National Research

Initiatives, having an office at 1895 Preston White Drive, Reston, VA 20191

("CNRI"), and the Individual or Organization ("Licensee") accessing and

otherwise using Python 1.6.1 software in source or binary form and its

associated documentation.

2. Subject to the terms and conditions of this License Agreement, CNRI hereby

grants Licensee a nonexclusive, royalty-free, world-wide license to reproduce,

analyze, test, perform and/or display publicly, prepare derivative works,

distribute, and otherwise use Python 1.6.1 alone or in any derivative version,

provided, however, that CNRI's License Agreement and CNRI's notice of copyright,

Rights Reserved" are retained in Python 1.6.1 alone or in any derivative version

prepared by Licensee. Alternately, in lieu of CNRI's License Agreement,

Licensee may substitute the following text (omitting the quotes): "Python 1.6.1

is made available subject to the terms and conditions in CNRI's License

Agreement. This Agreement together with Python 1.6.1 may be located on the

internet using the following unique, persistent identifier (known as a handle):

1895.22/1013. This Agreement may also be obtained from a proxy server on the

internet using the following URL: http://hdl.handle.net/1895.22/1013."

3. In the event Licensee prepares a derivative work that is based on or

incorporates Python 1.6.1 or any part thereof, and wants to make the derivative

work available to others as provided herein, then Licensee hereby agrees to

include in any such work a brief summary of the changes made to Python 1.6.1.

4. CNRI is making Python 1.6.1 available to Licensee on an "AS IS" basis. CNRI

MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED. BY WAY OF EXAMPLE,

BUT NOT LIMITATION, CNRI MAKES NO AND DISCLAIMS ANY REPRESENTATION OR WARRANTY

OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF

PYTHON 1.6.1 WILL NOT INFRINGE ANY THIRD PARTY RIGHTS.

5. CNRI SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON 1.6.1 FOR

ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS A RESULT OF

MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON 1.6.1, OR ANY DERIVATIVE

THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.

6. This License Agreement will automatically terminate upon a material breach of

its terms and conditions.

7. This License Agreement shall be governed by the federal intellectual property

law of the United States, including without limitation the federal copyright

law, and, to the extent such U.S. federal law does not apply, by the law of the

Commonwealth of Virginia, excluding Virginia's conflict of law provisions.

Notwithstanding the foregoing, with regard to derivative works based on Python

1.6.1 that incorporate non-separable material that was previously distributed

under the GNU General Public License (GPL), the law of the Commonwealth of

Virginia shall govern this License Agreement only as to issues arising under or

with respect to Paragraphs 4, 5, and 7 of this License Agreement. Nothing in

this License Agreement shall be deemed to create any relationship of agency,

partnership, or joint venture between CNRI and Licensee. This License Agreement

does not grant permission to use CNRI trademarks or trade name in a trademark

sense to endorse or promote products or services of Licensee, or any third

party.

8. By clicking on the "ACCEPT" button where indicated, or by copying, installing

or otherwise using Python 1.6.1, Licensee agrees to be bound by the terms and

conditions of this License Agreement.

CWI LICENSE AGREEMENT FOR PYTHON 0.9.0 THROUGH 1.2

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

.. parsed-literal::

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 Stichting Mathematisch Centrum or CWI not be used in advertising or

publicity pertaining to distribution of the software without specific, written

prior permission.

STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS

SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO

EVENT SHALL STICHTING MATHEMATISCH 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.

.. _BSD0:

ZERO-CLAUSE BSD LICENSE FOR CODE IN THE PYTHON |release| DOCUMENTATION

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

.. parsed-literal::

BSD 0-Clause License

.. _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 :mod:`uu` module 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.

* Permission to use, copy, modify, and distribute this software for any

* purpose without fee is hereby granted, provided that this entire notice

* is included in all copies of any software which is or includes a copy

* or modification of this software and in all copies of the supporting

* documentation for such software.

* THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED

* WARRANTY. IN PARTICULAR, NEITHER THE AUTHOR NOR LUCENT MAKES ANY

* REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY

* OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.

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

OpenSSL

-------

Authors

=======

This is the list of OpenSSL authors for copyright purposes.

It does not necessarily list everyone who has contributed code,

since in some cases, their employer may be the copyright holder.

To see the full list of contributors, see the revision history in

source control.

Groups

------

* OpenSSL Software Services, Inc.

* OpenSSL Software Foundation, Inc.

Individuals

-----------

* Andy Polyakov

* Ben Laurie

* Ben Kaduk

* Bernd Edlinger

* Bodo Möller

* David Benjamin

* David von Oheimb

* Dmitry Belyavskiy (Дмитрий Белявский)

* Emilia Käsper

* Eric Young

* Geoff Thorpe

* Holger Reif

* Kurt Roeckx

* Lutz Jänicke

* Mark J. Cox

* Matt Caswell

* Matthias St. Pierre

* Nicola Tuveri

* Nils Larsch

* Patrick Steuer

* Paul Dale

* Paul C. Sutton

* Paul Yang

* Ralf S. Engelschall

* Rich Salz

* Richard Levitte

* Shane Lontis

* Stephen Henson

* Steve Marquess

* Tim Hudson

* Tomáš Mráz

* Ulf Möller

* Viktor Dukhovni

The modules :mod:`hashlib`, :mod:`posix`, :mod:`ssl`, :mod:`crypt` use

the OpenSSL library for added performance if made available by the

operating system. Additionally, the Windows and macOS installers for

Python may include a copy of the OpenSSL libraries, so we include a copy

of the OpenSSL license here. For the OpenSSL 3.0 release,

and later releases derived from that, the Apache License v2 applies::

Apache License

Apache License, Version 2.0

expat

-----

The :mod:`pyexpat <xml.parsers.expat>` extension is built using an included copy of the expat

sources unless the build is configured ``--with-system-expat``::

and Clark Cooper

MIT License

libffi

------

The :mod:`!_ctypes` C extension underlying the :mod:`ctypes` module

is built using an included copy of the libffi

sources unless the build is configured ``--with-system-libffi``::

MIT License

zlib

----

The :mod:`zlib` extension is built using an included copy of the zlib

sources if the zlib version found on the system is too old to be

used for the build::

Zlib Data Compression Library License

cfuhash

-------

The implementation of the hash table used by the :mod:`tracemalloc` is based

on the cfuhash project::

This code is released under the BSD license:

BSD 3-Clause License

libmpdec

--------

The :mod:`!_decimal` C extension underlying the :mod:`decimal` module

is built using an included copy of the libmpdec

library unless the build is configured ``--with-system-libmpdec``::

BSD 2-Clause License

W3C C14N test suite

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

The C14N 2.0 test suite in the :mod:`test` package

(``Lib/test/xmltestdata/c14n-20/``) was retrieved from the W3C website at

https://www.w3.org/TR/xml-c14n2-testcases/ and is distributed under the

3-clause BSD license::

Redistribution and use in source and binary forms, with or without

modification, are permitted provided that the following conditions

are met:

* Redistributions of works must retain the original copyright notice,

this list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the original copyright

notice, this list of conditions and the following disclaimer in the

documentation and/or other materials provided with the distribution.

* Neither the name of the W3C nor the names of its contributors may be

used to endorse or promote products derived from this work without

specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Audioop

-------

The audioop module uses the code base in g771.c file of the SoX project.

https://sourceforge.net/projects/sox/files/sox/12.17.7/sox-12.17.7.tar.gz

This source code is a product of Sun Microsystems, Inc. and is provided

for unrestricted use. Users may copy or modify this source code without

charge.

SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING

THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR

PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.

Sun source code is provided with no support and without any obligation on

the part of Sun Microsystems, Inc. to assist in its use, correction,

modification or enhancement.

SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE

INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE

OR ANY PART THEREOF.

In no event will Sun Microsystems, Inc. be liable for any lost revenue

or profits or other special, indirect and consequential damages, even if

Sun has been advised of the possibility of such damages.

Sun Microsystems, Inc.

2550 Garcia Avenue

Mountain View, California 94043

asyncio

----------

Parts of the :mod:`asyncio` module are incorporated from

`uvloop 0.16 <https://github.com/MagicStack/uvloop/tree/v0.16.0>`_,

which is distributed under the MIT license::

MIT License