The rumor is they’re putting a screen in the outside that in effect makes the goggles look transparent, like ski goggles almost, by displaying the users eyes on the outside screen.
If you are doing AR and interacting with people who are physically in the room with you, but your eyes are blocked entirely by opaque goggles, it’s a weird social interaction. You’ll feel like you’re making eye contact, but they’re just staring at your blindfold looking goggles.
So the outward facing screen is to make the goggles look transparent-ish.