I think it must be a semi-transparent screen. Because otherwise the interior cameras would need some sort of illumination inside the goggles, which would be ver

I think it must be a semi-transparent screen. Because otherwise the interior cameras would need some sort of illumination inside the goggles, which would be very distracting and draining on your eyes. Edit: Whelp, I was wrong. I wrote this before they had announced the method on the keynote. Turns out you are creating a digital scan of your face, that is dynamically rendered based on the perspective of the outside observers in realtime. Quite impressive. Possibly overengineered. But But arguably a necessary feature to make this feel more friendly to other non-headset users and family members or coworkers.