Hi Dr. Solovay,
I'm excited to hear that you're interested in Ghilbert!
You can use the invitation code on this page to create an account on the server:
All of the git content is available at https://ghilbert-app.appspot.com/git (canonically) or mirrored at (e.g.) https://github.com/abliss/ghilbert-app.git . You will want to pull from a mirror for your first "git clone", since the appspot git server has some performance problems.
If you need more details on the git repositories, you can read about it at http://ghilbert-app.appspot.com/wiki/Git and send any questions you may have to this list.
I hope this isn't a double post. I'm not sure where the Invite codes (I got one from Raph) are used.