The XML files are in /usr/share/livewp/external_theme/

For the purposes of LiveWallpaper, the Window Name value is very important, as that's the way it finds the application window to send it to the Hildon background.

Reading through the Live Wallpaper source code is helpful. I'll have to find some more time for that. It's a good way to get the feet wet for development, anyway. I have a lot of ideas, but I don't have the experience yet to put them into practice.