What does the 'Userspace file system' Compiz plugin do?
What does this plugin do?
It does not appear to be possible to enable it using Compiz from the repositories, but I would still like to learn what the plugin does so I can decide whether it might be useful to me.
It just maps compiz options to a filesystem using a FUSE mount. So you can have /foo/compiz/plugins/move/screen0/options/whatever and that lets you get/set the whatever option in the move plugin.
It's entirely worthless and as far as I'm aware has never actually been used for anything. davidr apparently got bored and people keep making sure it compiles so it never gets removed.