bazaar
Bazaar (``bzr``) is a decentralized revision control system, designed to be
easy for developers and end users alike. Bazaar is part of the GNU project
to develop a complete free operating system.
Bazaar was formerly known as Bazaar-NG. It's the successor to ``baz``, a
fork of GNU arch, but shares no code. (To upgrade from Baz, use the
``baz-import`` command in the bzrtools plugin.)