I can't get the picture to open in full size because my internet is being a twat. However, I'm pretty sure that the hose actually goes to your brake pedal, not the clutch. It is for the cruise control. When the brake pedal is pressed, it opens an air valve and relieves the vacuum in the cruise control shutting it off. The other side of it goes into the driver's side fender where all the cruise control vacuum canisters and controls are.
Kurt