This gEdit plugin shows the git branch for the file being edited on the status bar. The master branch now contains the plugin compatible with Gnome 3 and the new API. The gnome2 branch contains the old version.
On Ubuntu and Debian, just install the make, python3-git and gettext packages, then install as described below.
Either download the files (using the Downloads button) and uncompress to a folder, or clone the repository.
Run sudo make install to install.
You can add my Ubuntu PPA to add this plugin as a software package and receive updates.
See https://launchpad.net/~denis-fuenzalida/+archive/ppa
On gEdit, go to Edit > Preferences, on the Plugins tab look for Git branch on status bar and mark the checkbox next to it to enable the plugin.
Obligatory screenshot:
On the image above, the branch name is super-improved-look-branch.
Note that it currently supports English and Spanish.