Vacuum? ports on throttle body

["Smith, Kirby A" <kirby.a.smith@lmco.com>]

Yesterday, while searching for vacuum leaks, I discovered that the throttle
body on my 1988 90q has two brass ports facing toward the front of the car,
one with a white base and one with a black base, only one of which was
covered by a plug.  Examination of my wife's car showed both of the ports on
her car were plugged.  Working under the assumption that it is easier for
parts to fall off than fall on, I plugged the open one one my car.  The
begged question is:  what are these ports for?  I did not find any
illustration of them in my Bentley, nor have I noticed any directions for a
VAG-nnnn to be hooked up to them.

TIA

                .... Kirby   (Kirby A. Smith)
                              2 x 1988 90q
                          New Hampshire USA