On a recent inspection when evaluating the exterior vent penetrations I came across an unusual configuration. I stated to my client I would need to see the inside to determine. Turns out whatever vented through the opening was sealed with the unusual cover. They improperly cut portions of the floor joists.
It must of been the same person who used for a furnace intake vent a glass block window, dryer exterior vent cover, duct tape, no glue at fittings, supported with angle iron at the return duct system. For your enjoyment I added some photos.
Also the dryer exterior vent was broken, (Not a big deal) and one of the bath vent covers was improperly installed and the bath vents terminated in the attic.
Seems like every vent termination on the outside was messed up on the outside and inside. Makes me think it was the same person.