[TN Traveler]

Getting the old Cougar ready for another road trip...

I pulled all roof vent covers for inspection and ended up having a few questions about a vent on my roof. There are six questions nested in this thread.

In the first photo, at the bottom right are two chrome circular vents: these are clearly the furnace exhaust vents. The white vent panel above these opens to access the rear of the refrigerator. This large plastic vent:

Is it a fresh air intake for the refrigerator?
Does it serve any other purpose?

My next photo shows the roof vent I also have questions about.
Once I removed four screws I was able to remove the rain / weather cover and exposed a vent opening approximately 6" wide and 24" long with integrated wire screen. This vent is directly above the aforementioned vents on the side of the Cougar.

Looking through the wire mesh, I see ~ 1 1/4" black pvc looking pipe. I assume this is a vent pipe and I also assume it is not a black tank vent.
This pipe is nestled in a corner and is actually about 50% under the lip of the screen and certainly does not have maximum vent capacity in its current location.
What is this pipe as shown in the 3rd photo?

Finally, looking through the wire mesh, I note what appears to be HVAC sealant tape that only covers ~25" of the rectangular vent and some of that is curling askew as shown in photo 4.

Hoping this is not too much for one thread...
Do I need to square that pipe up and secure it with a bracket?
Do I need to remove this vent cover, properly replace the duct tape and then reseal the whole unit back in place?

I believe I would have to cut the lap sealant, possibly remove a few retaining screws, make the repairs, reinstall the screws in the cover and then reseal. Correct?