Mystery vacuum line 190D

[W2014life]

Car: 1984 190D 2.2L

I was in the engine bay today replacing a worn engine shock. Upon removal of the plastic intake to get additional working space I made an interesting discovery. There was a broken clear vacuum line that was sticking out of a bundle of lines (image 1). The bundle works its way from the center of the engine to the driver’s side fender (image 2) right next to the glow plug relay where it then connects into a rubber 3-way (image 3). The 3-way contains two black lines, one of which looks like it travels into the cabin because I lost it right before the fuse box.

Anyone have any idea where the clear line should be connected, if this clear vacuum line is of any importance and what the black vacuum lines are?