I'm trying to find out what exactly all the capabilities are needed for but I am unable to find any detailed overview. For example, MultimediaDD - what do I need it for? The only thing I could find is the useless "to access multimedia device drivers". Access how? Which drivers? When would that be needed? What APIs use it?

I would like to get comprehensive info on all these but the only thing I see is vague marketing documentation. Is there any useful info about this at all? I have no idea what kind of a certificate I need if I can't see what they allow me to do.