gitk

See the main git repository for current versions:

 git clone git://www.kernel.org/pub/scm/gitk/gitk.git/

The man page: http://www.kernel.org/pub/software/scm/git/docs/gitk.html

Displays a complete repository history or a selected set of commits or a specific branch. This includes visualizing the commit graph, showing information related to each commit, and the files in the trees of each revision.

Historically, gitk was the first repository browser. It's written in Tcl/Tk and almost the whole development history is present in the repository as referenced to on top of this page. Regularly merges are performed in the main git repository.

Despit being the first repo browser for git, it is still an excellent one. Despite being written in a scripting language, it provides a very good responsiveness, also compared with other - more recent - browsers.