This is an Emacs VC back-end for the Game of Tree version control system
It's available on ELPA: to install it just M-x package-install RET vc-got RET; vc-got will register itself, there's no need to
require it.
While I've been using this backend on a daily basis for the last years, there are some rough edges. Fetching updates in particular is one action that at the moment is better to do by hand. Pushing, committing, blaming etc on the other hand are fully functional.
Note that pushing requires at least got 0.56, other functionalities should work with older versions.
vc-got is on ELPA and thus a FSF copyright assignment is required. It's really easy to get one (just send an email), and having one will allow you to make further contribution to Emacs itself or to various other packages.