Plastic Vent Cover Next to Gas Cap

I have a 2020 Rubicon 520. Does anyone know what the small plastic piece on the collar around the gas cap is for? It is a small piece of plastic on the outside collar. The schematic says it is a vent cover of some sort. At first look it looks like it can be pulled off but it’s screwed down from underneath. I took it off but there is no tube or vent. Looks like there should be a tube there.