After doing repair work to the two manifolds, the turbo and the oil filter container, I noticed I had one small part left over?

Thank you, Steve, for responding. Here are two images of this part. This time, thankfully, they went through!
Richard

Thank you very much, Steve, for your reply. This is what I did:

1. I disassembled both manifolds--air and exhaust, and the Garrett T3 turbo (all at the same time). After I de-greased and sandblasted these three items, I put everything together with the assistance of a lot of YouTube videos. I also used my Haynes Mercedes manual.
2. Once everything was put together, I tried to start the engine and guess what. It started! The moment I got a heart attack was when I went back to my work table and saw this little part. I did what research I could, couldn't identify it, and so reached out to you.
3. The goal of this whole exercise was to stop the leaking permanently from the engine and tranny. So, my next step was to test drive the car. It drove fine, but the next morning, I discovered three oil runs on the floor of my garage--oil stains worse and different than before.
I hope this information will shed some light as to where this part goes.
Richard