The toolbar on the left shows your branches and tags. The log of the currently selected one is displayed.
When selecting a revision the diff of this specific commit is displayed in the right panel.
On top of the right panel, you can choose 'Tree' to display the versioned content at the specific revision selected in the left panel. You can browse through directories and display file contents.
Other people on your network have read-only access to your repository: they may access to the web interface (without 'Workspace'), clone or pull from your repository. All this through the same url:
Clone:
$ git clone http://<ip_of_the_computer_running_webui>:8000/ repo_name
Pull:
$ git pull http://<ip_of_the_computer_running_webui>:8000/
Commits can only be made from localhost.
The diff view lets you review the differences of the selected file. You can select code in more fine grained way: