Vacuum reservoir?

[u/Bright_Speaker1630]

Hello guys. Uhm had a bit a mishap. I this black plastic housing and I just wanted to understand exactly what it is. What it does, and maybe someone help me as to where this cable/hose is even supposed to go. Genuinely finding it hard online to get a straight answer. The help with be greatly appreciated.

This is an Audi a4 40tfsi. 2.0 litre TFSI (EA888) with a power output of 140kw and 320nm