Missing Vacuum Hose

B16a- Right above my throttle there is a circular disc with a male vacuume attatchment, and I have no vacuum hose hooked up to it. Bought the car about 2 months ago, and just noticed it. So, two questions, where does the hose go, and what does it do? I'm a noob to this engine, and somewhat a noob to engines. Thanks in advance

Slacky

1990 CRX B16a

The b16a I had came out of the shop that did the swap with the same hose you are describing just hanging there. It never affected anything however. dont know what it is intended for.