RNGzip is a schema-based compressor for XML. It is copyright ©2007 by Christopher League and distributed under the GNU General Public License. It is partly described in our paper “Type-based compression of XML data,” Proc. IEEE Data Compression Conference, March 2007.

Web page: http://contrapunctus.net/league/haques/rngzip/
Bundled release:

Introduction
explains the purpose of RNGzip, with a simple use case.
Installation
shows how to obtain and build RNGzip.
Usage
is a reference for all the options and capabilities of RNGzip.
Caveats
lists some potential problems you may encounter, and some ideas for future development.
License
describes the copyright restrictions for this program and acknowledges the authors of some of its components.
API
contains the Javadoc reference for the code (not pre-built in the distribution, but you can create it using make api-docs or make all-api-docs