To me, looking at the photographs, the line seems to be coming from the bottom of the air intake throttle housing.
Some engines had a swap, where the vacuum line needs to be positioned after rather than before the butterfly flap - or something along those lines. If that was done on your car, it's possible there are two vacuum lines, an original one and an extra, newly installed one, and the one that is not needed was 'plugged' in this messy way. Just a guess.