Does anyone know what this is?
 

I’ve bought a 2013 used Acura RDX AWD base model, but there seems to be a piece missing and i don’t know what it’s for.
https://cimg6.ibsrv.net/gimg/www.acu...3cd9b5709.jpeg
2013 Acura RDX AWD base model. What is this piece called, I bought a used one and it seems to be missing the cover and is just a hole with the plastic lining.