After looking at the photo below, I noticed it appears that only the outboard side of the #4 engine cowling is open (moved aft) - thus exposing the cascade thrust reverser.
This has me wondering ...........
Are cascade type thrust reversers only located on the outboard side of the engine? Or is only the outboard half of the reverser deployed on this particular engine for some reason?
Photo © Garry Lewis - AirTeamImages