Unknown plastic nut/fastener

[wwo]

Hello everyone. I had my Golfs first oil change done a couple of days ago and found a strange fastener/nut on copilots seat. Sent a picture to the dealer and he said he had nothing to do with it nor even seen it prior stating that it didn't come from the car and it must have been there for the whole time.
I find that hard to believe since I vacuumed the whole car thorougly prior to bringing it there.
So I am turning to you if someone recognises it.
Thanks in advance!

 

[Maturedriver]

I think it’s the main engine mounting clip. If you every exceed the speed limit the engine will fall out

 

[wwo]

T

I think it’s the main engine mounting clip. If you every exceed the speed limit the engine will fall out

Thank you for your contribution.

 

[Maturedriver]

Pleased I could help. My mechanical knowledge is legendary .