Does anyone know what this bag is?

[Loppysaurusrex]

That white bag, it's inflated but I'm not sure what it is

 

[webby]

I'd have to dig up diagrams, but I believe it has to do with the sunroof draining down the roofline into the trunk there.

 

[Loppysaurusrex]

I'd have to dig up diagrams, but I believe it has to do with the sunroof draining down the roofline into the trunk there.

Ah, well anyhow it's not the source of my arch enemy aka trunk rattles

It's actually this vent

When the bass hits it makes the flaps open and shut making audio noise

Do you think it's fine if I tape them open or something?