My guess is that it’s probably this thing shown during eurobike last year. I am budgeting for it already.
Full article at https://bikeboard.at/Board/Profile-Design-Neuheiten-2017-th226265
Wow. An unrevealed feature and no speculation from ST on what it is?
My guess is that it will eventually mount a rearward Profile-designed bento box (without bolts on the frame) or a frontward Profile-designed aero bottle without additional hardware. I don’t see a computer mount requiring more mass from the stem.