Three of the features Apple named for the iPhone Duo exist to put something on a screen the person holding the phone cannot see. Duo Preview, Kid Cue and Duo FaceTime all run on the 5.4-inch outer display, facing whoever is in front of the camera. The 48MP Fusion Main camera the outer display previews…
Duo FaceTime
How to Use Duo FaceTime on iPhone Duo: Letting Nearby Friends Join From the Outer Display
Duo FaceTime is an iPhone Duo feature that lets nearby friends join a FaceTime call from the phone’s 5.4-inch outer display while you stay on the 7.6-inch inner display, so two groups on opposite sides of one phone can be on the same call. Apple lists it as one of four features exclusive to iPhone…