The lists below should be arranged in ascending alphabetical order (excluding "Version Control Systems" which should be stated first). When specifying release dates please use the format YYYY-MM-DD.
Version Control
The following applications related to version/revision control are written in Python:
Version Control Systems
Abstraction Layers and Tools
Tools with unified interface to several version control systems.
Hg-Git - access Git repositories from Mercurial
pysync - abstraction layer, looks inactive, but a lot of commits
pyvcs (Alex Gaynor and co.) - pure python abstraction layer of multiple VCS, very lightweight
vcs - another abstraction layer, seems to be MIT licensed
Migration Tools
cvs2svn - the CVS to Subversion repository converter
Tailor - a tool to migrate changesets between ArX, Bazaar, Bazaar-NG, CVS, Codeville, Darcs, Git, Mercurial, Monotone, Subversion and Tla repositories
Repository Browsers
Trac supports repository browsing
ViewVC (formerly ViewCVS) - a repository browser for CVS and Subversion