Happy new year folks.
I would appreciate it if someone can identify the silver canister very near the turbo on a 603.971 as installed on a 1992 300SD.

What does it do? And where is the vacuum line connected? (I am assuming it's a vacuum line).

And why do I see quite a few cars with it disconnected!?

This item can be seen in pictures 9 and 10 of post # 13 in this thread:
92 300SD W140 engine head

Thank you.