copying.txt

# NVDA License

NVDA is available under the GNU General Public License version 2, with two special exceptions.
The exceptions are outlined in the sections "Non-GPL Components in Plugins and Drivers" and "Microsoft Distributable Code".
NVDA also includes and uses components which are made available under different free and open source licenses.
Information about how to obtain and build the code for yourself is available at http://community.nvda-project.org/wiki/AccessingAndRunningSourceCode
All applicable licenses are included below.

## GNU GENERAL PUBLIC LICENSE

https://www.gnu.org/licenses/old-licenses/gpl-2.0.html

Version 2, June 1991

    Copyright (C) 1989, 1991 Free Software Foundation, Inc.  
    <https://fsf.org/>

    Everyone is permitted to copy and distribute verbatim copies
    of this license document, but changing it is not allowed.

### Preamble

The licenses for most software are designed to take away your freedom
to share and change it. By contrast, the GNU General Public License is
intended to guarantee your freedom to share and change free
software--to make sure the software is free for all its users. This
General Public License applies to most of the Free Software
Foundation's software and to any other program whose authors commit to
using it. (Some other Free Software Foundation software is covered by
the GNU Lesser General Public License instead.) You can apply it to
your programs, too.

When we speak of free software, we are referring to freedom, not
price. Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for
this service if you wish), that you receive source code or can get it
if you want it, that you can change the software or use pieces of it
in new free programs; and that you know you can do these things.

To protect your rights, we need to make restrictions that forbid
anyone to deny you these rights or to ask you to surrender the rights.
These restrictions translate to certain responsibilities for you if
you distribute copies of the software, or if you modify it.

For example, if you distribute copies of such a program, whether
gratis or for a fee, you must give the recipients all the rights that
you have. You must make sure that they, too, receive or can get the
source code. And you must show them these terms so they know their
rights.

We protect your rights with two steps: (1) copyright the software, and
(2) offer you this license which gives you legal permission to copy,
distribute and/or modify the software.

Also, for each author's protection and ours, we want to make certain
that everyone understands that there is no warranty for this free
software. If the software is modified by someone else and passed on,
we want its recipients to know that what they have is not the
original, so that any problems introduced by others will not reflect
on the original authors' reputations.

Finally, any free program is threatened constantly by software
patents. We wish to avoid the danger that redistributors of a free
program will individually obtain patent licenses, in effect making the
program proprietary. To prevent this, we have made it clear that any
patent must be licensed for everyone's free use or not licensed at
all.

The precise terms and conditions for copying, distribution and
modification follow.

### TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

**0.** This License applies to any program or other work which
contains a notice placed by the copyright holder saying it may be
distributed under the terms of this General Public License. The
"Program", below, refers to any such program or work, and a "work
based on the Program" means either the Program or any derivative work
under copyright law: that is to say, a work containing the Program or
a portion of it, either verbatim or with modifications and/or
translated into another language. (Hereinafter, translation is
included without limitation in the term "modification".) Each licensee
is addressed as "you".

Activities other than copying, distribution and modification are not
covered by this License; they are outside its scope. The act of
running the Program is not restricted, and the output from the Program
is covered only if its contents constitute a work based on the Program
(independent of having been made by running the Program). Whether that
is true depends on what the Program does.

**1.** You may copy and distribute verbatim copies of the Program's
source code as you receive it, in any medium, provided that you
conspicuously and appropriately publish on each copy an appropriate
copyright notice and disclaimer of warranty; keep intact all the
notices that refer to this License and to the absence of any warranty;
and give any other recipients of the Program a copy of this License
along with the Program.

You may charge a fee for the physical act of transferring a copy, and
you may at your option offer warranty protection in exchange for a
fee.

**2.** You may modify your copy or copies of the Program or any
portion of it, thus forming a work based on the Program, and copy and
distribute such modifications or work under the terms of Section 1
above, provided that you also meet all of these conditions:

  
**a)** You must cause the modified files to carry prominent notices
stating that you changed the files and the date of any change.

  
**b)** You must cause any work that you distribute or publish, that in
whole or in part contains or is derived from the Program or any part
thereof, to be licensed as a whole at no charge to all third parties
under the terms of this License.

  
**c)** If the modified program normally reads commands interactively
when run, you must cause it, when started running for such interactive
use in the most ordinary way, to print or display an announcement
including an appropriate copyright notice and a notice that there is
no warranty (or else, saying that you provide a warranty) and that
users may redistribute the program under these conditions, and telling
the user how to view a copy of this License. (Exception: if the
Program itself is interactive but does not normally print such an
announcement, your work based on the Program is not required to print
an announcement.)

These requirements apply to the modified work as a whole. If
identifiable sections of that work are not derived from the Program,
and can be reasonably considered independent and separate works in
themselves, then this License, and its terms, do not apply to those
sections when you distribute them as separate works. But when you
distribute the same sections as part of a whole which is a work based
on the Program, the distribution of the whole must be on the terms of
this License, whose permissions for other licensees extend to the
entire whole, and thus to each and every part regardless of who wrote
it.

Thus, it is not the intent of this section to claim rights or contest
your rights to work written entirely by you; rather, the intent is to
exercise the right to control the distribution of derivative or
collective works based on the Program.

In addition, mere aggregation of another work not based on the Program
with the Program (or with a work based on the Program) on a volume of
a storage or distribution medium does not bring the other work under
the scope of this License.

**3.** You may copy and distribute the Program (or a work based on it,
under Section 2) in object code or executable form under the terms of
Sections 1 and 2 above provided that you also do one of the following:

  
**a)** Accompany it with the complete corresponding machine-readable
source code, which must be distributed under the terms of Sections 1
and 2 above on a medium customarily used for software interchange; or,

  
**b)** Accompany it with a written offer, valid for at least three
years, to give any third party, for a charge no more than your cost of
physically performing source distribution, a complete machine-readable
copy of the corresponding source code, to be distributed under the
terms of Sections 1 and 2 above on a medium customarily used for
software interchange; or,

  
**c)** Accompany it with the information you received as to the offer
to distribute corresponding source code. (This alternative is allowed
only for noncommercial distribution and only if you received the
program in object code or executable form with such an offer, in
accord with Subsection b above.)

The source code for a work means the preferred form of the work for
making modifications to it. For an executable work, complete source
code means all the source code for all modules it contains, plus any
associated interface definition files, plus the scripts used to
control compilation and installation of the executable. However, as a
special exception, the source code distributed need not include
anything that is normally distributed (in either source or binary
form) with the major components (compiler, kernel, and so on) of the
operating system on which the executable runs, unless that component
itself accompanies the executable.

If distribution of executable or object code is made by offering
access to copy from a designated place, then offering equivalent
access to copy the source code from the same place counts as
distribution of the source code, even though third parties are not
compelled to copy the source along with the object code.

**4.** You may not copy, modify, sublicense, or distribute the Program
except as expressly provided under this License. Any attempt otherwise
to copy, modify, sublicense or distribute the Program is void, and
will automatically terminate your rights under this License. However,
parties who have received copies, or rights, from you under this
License will not have their licenses terminated so long as such
parties remain in full compliance.

**5.** You are not required to accept this License, since you have not
signed it. However, nothing else grants you permission to modify or
distribute the Program or its derivative works. These actions are
prohibited by law if you do not accept this License. Therefore, by
modifying or distributing the Program (or any work based on the
Program), you indicate your acceptance of this License to do so, and
all its terms and conditions for copying, distributing or modifying
the Program or works based on it.

**6.** Each time you redistribute the Program (or any work based on
the Program), the recipient automatically receives a license from the
original licensor to copy, distribute or modify the Program subject to
these terms and conditions. You may not impose any further
restrictions on the recipients' exercise of the rights granted herein.
You are not responsible for enforcing compliance by third parties to
this License.

**7.** If, as a consequence of a court judgment or allegation of
patent infringement or for any other reason (not limited to patent
issues), conditions are imposed on you (whether by court order,
agreement or otherwise) that contradict the conditions of this
License, they do not excuse you from the conditions of this License.
If you cannot distribute so as to satisfy simultaneously your
obligations under this License and any other pertinent obligations,
then as a consequence you may not distribute the Program at all. For
example, if a patent license would not permit royalty-free
redistribution of the Program by all those who receive copies directly
or indirectly through you, then the only way you could satisfy both it
and this License would be to refrain entirely from distribution of the
Program.

If any portion of this section is held invalid or unenforceable under
any particular circumstance, the balance of the section is intended to
apply and the section as a whole is intended to apply in other
circumstances.

It is not the purpose of this section to induce you to infringe any
patents or other property right claims or to contest validity of any
such claims; this section has the sole purpose of protecting the
integrity of the free software distribution system, which is
implemented by public license practices. Many people have made
generous contributions to the wide range of software distributed
through that system in reliance on consistent application of that
system; it is up to the author/donor to decide if he or she is willing
to distribute software through any other system and a licensee cannot
impose that choice.

This section is intended to make thoroughly clear what is believed to
be a consequence of the rest of this License.

**8.** If the distribution and/or use of the Program is restricted in
certain countries either by patents or by copyrighted interfaces, the
original copyright holder who places the Program under this License
may add an explicit geographical distribution limitation excluding
those countries, so that distribution is permitted only in or among
countries not thus excluded. In such case, this License incorporates
the limitation as if written in the body of this License.

**9.** The Free Software Foundation may publish revised and/or new
versions of the General Public License from time to time. Such new
versions will be similar in spirit to the present version, but may
differ in detail to address new problems or concerns.

Each version is given a distinguishing version number. If the Program
specifies a version number of this License which applies to it and
"any later version", you have the option of following the terms and
conditions either of that version or of any later version published by
the Free Software Foundation. If the Program does not specify a
version number of this License, you may choose any version ever
published by the Free Software Foundation.

**10.** If you wish to incorporate parts of the Program into other
free programs whose distribution conditions are different, write to
the author to ask for permission. For software which is copyrighted by
the Free Software Foundation, write to the Free Software Foundation;
we sometimes make exceptions for this. Our decision will be guided by
the two goals of preserving the free status of all derivatives of our
free software and of promoting the sharing and reuse of software
generally.

**NO WARRANTY**

**11.** BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO
WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.
EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR
OTHER PARTIES PROVIDE THE PROGRAM "AS IS" 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
PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME
THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

**12.** IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN
WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY
AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU
FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR
CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE
PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A
FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF
SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
DAMAGES.


## Non-GPL Components in Plugins and Drivers

Plugins and drivers, including those provided by third parties, are considered derivative works of NVDA and must therefore be licensed under the terms of the GNU General Public License version 2.
As a special exception, an NVDA plugin or driver (as defined in the NVDA Developer Guide) may use components under other licenses provided that:
a) Any such component does not prevent the NVDA plugin or driver from being licensed under the terms of the GNU General Public License version 2; and
b) Any such component does not directly use and is not directly used by any portion of NVDA outside of that plugin or driver.
For example, a speech synthesizer driver may use a speech synthesiser under a proprietary license.
In contrast, in a plugin providing support for an application, the code which implements any interface provided by NVDA must be licensed under the GNU General Public License version 2.


## Microsoft Distributable Code

This applies to the following files:
- mfc*.dll
- Microsoft.VC*.manifest
- msvc*.dll

As a special exception to the GNU General Public License version 2, these components may be included with binary distributions of NVDA without being subject to the terms of that license.

Microsoft Distributable Code is covered by the following terms:

You may not
a) alter any copyright, trademark or patent notice in the Distributable Code;
b) use Microsoft's trademarks in your programs' names or in a way that suggests your programs come from or are endorsed by Microsoft;
c) distribute Distributable Code to run on a platform other than the Windows platform;
d) include Distributable Code in malicious, deceptive or unlawful programs; or
e) modify or distribute the source code of any Distributable Code so that any part of it becomes subject to an Excluded License. An Excluded License is one that requires, as a condition of use, modification or distribution, that
 i) the code be disclosed or distributed in source code form; or
 ii) others have the right to modify it.

## Third-Party Dependencies

NVDA includes various third-party dependencies, each with its own license terms. 
Python pip modules with acceptable licences are automatically limited by our build system to include only BSD, MIT, Python, LGPLV3+ and Apache.

In addition to these dependencies, the following are also included in NVDA:

- eSpeak: GPL-3
- LibLouis: LGPL-3
- BrlAPI: LGPL-3
- IAccessible 2: Simplified BSD 
- Microsoft Detours: MIT 
- Python: PSF
- NSIS: zlib/libpng

Furthermore, NVDA also utilises some static/binary dependencies, details of which can be found at the following URL:

https://github.com/nvaccess/nvda-misc-deps/tree/master