What is this thing?

I don’t really understand what this piece is, a filter for the vent? It’s behind the panel that would be next to your calves if driving. Looks far too nasty to go back in if it’s a filter. Is it just sort of an insulation or spacer so I could put it back in with this condition? Are there repops of it? Trying to get the carpet done and can’t put that panel back in til I know what this is. Thanks
Author: Dylan Galvin