This host runs some phpMyAdmin demos. You have full control over the MySQL server, however you should not change root, debian-sys-maint or pma user password or limit their permissions. If you do so, demo can not be accessed until privileges are restored, so you just break things for you and other users. Feel free to try any of the phpMyAdmin features. If you break something, just wait a while. The database configuration resets every hour. Databases are cleaned every Monday morning, so do not expect that your data will stay there forever.
Login is root with empty password or any user you create.
Please note that git versions don't have to be working, that's why it's development version :-).