It's a simple over-running clutch- freewheels in one direction, takes load in the other. Functions like the freewheel on a bicycle, but I'll make no comment on how this thing is put together. No external controls.
BTW I don't know WHAT they're talking about re: "The idea of which was to reduce possibility of sudden snatch when coming down from high revs such as motorway driving to a standing stop thus prolonging the life of expensive automatic tensioners."
The tensioners is what they're worried about? Automatic tensioners are just spring loaded idler pulleys right? (Unless VW has concocted some sort of dumb*** expensive high-tech version for something simple and cheap
) The tensioners I've priced in the past are cheaper than this clutch thingie.