What is this port on the throttle body?

Passenger side, below the TPS and behind the vaccum lines which attach at the top of the plenum, there is a port on the throttle body. Mine is open. I do not feel a vaccum. I was thinking PCV. Any one know what this port is for?
Most people remove that. Like mentioned before, the coolant would circulate through the TB - Hot coolant at that.
it is used to help cold starts. as posted above they are no longer needed and help performance by removing the lines going to it.