The volume rocker orientation is they intend you to use this vertically when unfolded.
The dimensions are so close unfolded to the Ipad mini which exists in this format already. Which also has similar orientation of controls (volume and touch id) that the format is already worked out from their perspective.
Lets just hope there's no jelly-roll on the screen lol.
Leaked "official" dummy units reveal the final design of the iPhone Ultra/Fold and iPhone 18 Pro. While the iPhone 18 Pro remains mostly unchanged, the iPhone Ultra features Touch ID; unique top-mounted button placement. This design choice solves will most definitely divide the room. Apple is prioritizing the "iPad" state of the foldable iPhone, and some won't like that.