Bazaar-NG is an implementation of GNU arch from Canonical written in Python.
Arch is a version control system, which allows you to keep old versions of
files and directories (usually source code), keep a log of who, when, and
why changes occurred, etc., like SVN, CVS, or RCS. Arch is distributed, which
gives it significant advantages and some disadvantages compared to SVN and
CVS. The bzr implementation is the next Bazaar version from Canonical called
Bazaar-NG.

WWW: http://www.bazaar-ng.org/