Sonar has been designed to be extensible. Since we believe in the 'eat your own food' philosophy, Sonar is a suite of plugins that use the extension mechanism.
In order to configure those these plugins, log in as an administrator, go to Settings > Configuration > General Settings.
See also Plugin Versions Matrix.
Backup / Restore
The whole Sonar configuration can be backed up and restored. This includes: Quality profiles (rules + alerts), manual metrics, events categories, global settings section (plugins) and customization.