If you want to create a new page, PM one of the developers and he will create the page for you.
plug-ins You can also have your own private plug-ins that you can keep on the WDTV and activate on startup. In terms of content playable on the WDTV through UMSP, refer to the information here link (not up to date) The UMSP server is activated by the /etc/init.d/S68umsp process.
The list: UMSP Plugin – Stream media from the internet to your TV.
Media Mark Plugin – Puts a tick next to files which you have viewed in the past. Media Navigation Plugin – Better fast forward and rewind functionality that is provided by the default firmware.
The wiki pages and general WDLXTV documentation is the responsibility of the users!
The developers have limited time to play with new features and to work on the code and integration, so they usually don't want to spend more time writing documentation.