Plastic Inside Where You Fill up Oil

I just thought I’d check my oil level in my G4 Prius 

The oil was fine but I took off the oil filler cap just to take a look as I’ve never taken it off before as I’ve not needed to.  What I did notice was a strip of plastic (white I think) that is just below the cap 

I am just wondering what this piece of plastic is as my previous Prius (MK 2) I don’t think had that 

3 hours ago, ninanina said:

I just thought I’d check my oil level in my G4 Prius 

The oil was fine but I took off the oil filler cap just to take a look as I’ve never taken it off before as I’ve not needed to.  What I did notice was a strip of plastic (white I think) that is just below the cap 

I am just wondering what this piece of plastic is as my previous Prius (MK 2) I don’t think had that 

Can you take a pic?

Best guess, it's a shield to stop oil spray hitting the underside of the filler cap when the engine is running. If you look it only leaves a narrow gap along the rear edge to allow oil to flow past when re-filling. Had to take my cap off to have a look as I've never had to add oil between services. As the car has never been touched by anyone other than the local main agent it must be a standard fitment.