Suzuki sidekick hydraulic clutch

In my 98 sidekick clutch fluid line there is a device clipped on the firewall 8 inches below the master cyl which is termed #10 in one factory diagram. Its description is “valve assembly throttle”.
Or in another diagram, see below, it is labeled #5 clutch throttle valve.
It has been commented on in a couple of forums but no one can say what its actual purpose is. Anyone know?

Are you certain this device is part of the clutch fluid line? i.e. the fluid line from the clutch master cylinder to the slave cylinder? I’m thinking it is part of the throttle function, you know, when you press on the gas pedal, and there’s some clutch mechanism involved with that, and this gadget does it. Just an educated guess, but it may not have anything to do with the manual transmission’s clutch or clutch hydraulics.

the line on the top comes from the clutch master cyl and the output is the feed to the slave cyl. no mistaking that.

Throttling means restricting (that is perhaps oversimplifying it). But the purpose of a throttling valve seems hard to explain: http://www.physicsforums.com/showthread.php?t=67757