It's black & soft on my 2017. It's mostly out of view, but you can feel it after the wheelwell liners are out & a little of it peeks out where the doublewall piece ends. It's like it is expanding foam - they must caulk a bead of it thinking it is going to seal the cavity, but in reality it's promoting moisture to be held there. I know a lot of this foam (maybe all of it) is meant to deaden sound. The white foam is used extensively in all the Brampton-built vehicles - in the rockers, door jambs, quarter cavities, etc. New Challengers are rusting in the rockers & ahead of the rear wheels in the quarters in very short order. Many Challenger owners have been pleading with Chrysler to STOP using this foam, but it's falling on deaf ears.

On the rear areas in my Ram, it is IMPOSSIBLE to remove this foam - you can barely get your hand in there to feel it. My 2008 Ram did not have this - I was able to Texaco those areas effectively.