To make it easier to add or remove functions for Freevo, we integrated a plugin system into Freevo. By adding a file into the Freevo system, you can add new functions without changing anything else in the core of Freevo. It's also possible to distribute a plugin with your application and not within the Freevo distribution.
If you wrote a plugin, please send it to the Freevo developer list. Maybe other people also find it usefull.