Dryer vent question...pic included

[David Nasser]

Does anybody know what this square stucture is below the dryer vent?

This is a laundry room on the upstairs of a Condo.

Its partially open...looks like a missing screw.

David

[David P. OKeefe]

Where's the pic?

[Bruce M. Graham]

Can't tell it's out of focus.

[Michael Larson]

Where the lights on for that pic?

[Jeffrey R. Pope]

It's a clean-out (no picture needed). . .

[Wayne B. Wilson]

Micheal it was taken with white light Why can you not clearly see it? I concur with Jeff

[sparksnmore]

My guess is it's a make up air duct that someone hap-haphazardly capped off.
Was the dryer in a closet with a solid door?