Does this type of roof vent open at all?

You have to clean it out from in the attic. Detach the pipe going to it at the ceiling and stick your hand in there and pull out the lint.

That seems so much easier than the bullshite I just typed.

Yeah that definitely sounds like a better idea.

I think I posted a thread here about a vent like that a couple of years ago. I made the roofer come back and change it to a dryer specific one with a flapper.

I had this same type of dryer vent through the roof. It took forever for our clothes to dry. We finally started exploring going through the wall and brick to vent it outside. But we weren't sure if it would if our new vent was even possible since it would either hit on the porch or in the wall between the garage and brick. We drilled a small pilot hole. Turns out it came out perfectly in the corner on our front porch. Not sure why the damn builder didn't do that to begin with. But it completely solved our slow drying clothes situation.