I removed the plastic rear bumper cover from my '96 ES-300 and was surprised to find this fixture, which I guess is a vent or breather of some kind.

I'm not clear on why a trunk would need such a fixture, and as you can see, at the first touch the louvers disintegrated and one fell to the floor. I am thinking of replacing it with a bit of Gorilla tape.
Is there something I'm missing?

 

That vent is to allow cabin pressure equalization.

 

Do not tape the vent. It’s to help the doors and the trunk close smoothly without air pressure pushing out from the inside.