Idle return controller

[ttodaro8641]

Hello... I'm brand new to the forum so please take into account that some procedural errors may be made by me. I need some help with a 1969 911T with Weber carbs. On the throttle cross shaft there is an electrically controlled vacuum valve that appears to regulate throttle closing. Can anyone tell me what the name of this system is? Also where can I find operating and setup info?

[911obgyn]

Probably a vacuum operated decel valve.
So throttle doesn’t slam shut and stall.