XZ Utils Licensing ================== Different licenses apply to different files in this package. Here is a rough summary of which licenses apply to which parts of this package (but check the individual files to be sure!): - liblzma is under the BSD Zero Clause License (0BSD). - The command line tools xz, xzdec, lzmadec, and lzmainfo are under 0BSD except that, on systems that don't have a usable getopt_long, GNU getopt_long is compiled and linked in from the 'lib' directory. The getopt_long code is under GNU LGPLv2.1+. - The scripts to grep, diff, and view compressed files have been adapted from GNU gzip. These scripts (xzgrep, xzdiff, xzless, and xzmore) are under GNU GPLv2+. The man pages of the scripts are under 0BSD; they aren't based on the man pages of GNU gzip. - Most of the XZ Utils specific documentation that is in plain text files (like README, INSTALL, PACKAGERS, NEWS, and ChangeLog) are under 0BSD unless stated otherwise in the file itself. The files xz-file-format.txt and lzma-file-format.xt are in the public domain but may be distributed under the terms of 0BSD too. - Doxygen-generated HTML version of the liblzma API documentation: While Doxygen is under the GNU GPLv2, the license information in Doxygen includes the following exception: Documents produced by doxygen are derivative works derived from the input used in their production; they are not affected by this license. Note: The JavaScript files (under the MIT license) have been removed from the Doxygen output. - Translated messages and man pages are under 0BSD except that some old translations are in the public domain. - Test files and test code in the 'tests' directory, and debugging utilities in the 'debug' directory are under the BSD Zero Clause License (0BSD). - The GNU Autotools based build system contains files that are under GNU GPLv2+, GNU GPLv3+, and a few permissive licenses. These files don't affect the licensing of the binaries being built. - The extra directory contain files that are under various free software licenses. For the files under the BSD Zero Clause License (0BSD), if a copyright notice is needed, the following is sufficient: Copyright (C) The XZ Utils authors and contributors If you copy significant amounts of 0BSD-licensed code from XZ Utils into your project, acknowledging this somewhere in your software is polite (especially if it is proprietary, non-free software), but it is not legally required by the license terms. Here is an example of a good notice to put into "about box" or into documentation: This software includes code from XZ Utils <https://tukaani.org/xz/>. The following license texts are included in the following files: - COPYING.0BSD: BSD Zero Clause License - COPYING.LGPLv2.1: GNU Lesser General Public License version 2.1 - COPYING.GPLv2: GNU General Public License version 2 - COPYING.GPLv3: GNU General Public License version 3 A note about old XZ Utils releases: XZ Utils releases 5.4.6 and older and 5.5.1alpha have a significant amount of code put into the public domain and that obviously remains so. The switch from public domain to 0BSD for newer releases was made in Febrary 2024 because public domain has (real or perceived) legal ambiguities in some jurisdictions. There is very little *practical* difference between public domain and 0BSD. The main difference likely is that one shouldn't claim that 0BSD-licensed code is in the public domain; 0BSD-licensed code is copyrighted but available under an extremely permissive license. Neither 0BSD nor public domain require retaining or reproducing author, copyright holder, or license notices when distributing the software. (Compare to, for example, BSD 2-Clause "Simplified" License which does have such requirements.) If you have questions, don't hesitate to ask for more information. The contact information is in the README file.