BikeRadar has the scoop. Some highlights:
A single-lever, double-tap shifter setup similar to the road system.
Smaller cage options (medium and short), given the reduced chainring capacity.
Possibly carbon crank arms. Chainring teeth options speculated include 26/39, 28/42 and 30/44T. Cassette options: 11-32, 11-34, 11-36T.
Bipartite rotors, alloy spider, steel donut.
Here’s the visual: