Implementation
An implementation of the xz file format is freely available online as XZ Utils. It is licensed under the terms of the GNU LGPL and GNU GPL, with the bulk of the software (e.g., liblzma) in the public domain. Version 1.22 of GNU tar supports using this software to handle xz files transparently. FreeBSD tar has supported xz transparently since r191190 (released on April 17, 2009).
7-Zip has supported xz since version 9.04 beta (stable since 9.20).
Read more about this topic: Xz