The sample application you are currently viewing is intended to demonstrate the integration of RoboGuice, a dependency injection (DI) framework for Android. Integration points include the usage of view injection, singletons, and event binding, as well as support for unit testing. This uses the 3.x version for its improved performance and simpler usage.
Disclaimer: This is not intended to be a full-fledged project; as such some of the usage explores what could be done, not what should be done.