IBridge

iBridge is a family of embedded processing devices for Macs. There are currently two major variants.
 * iBridge T1 - found in the 2016 MacBook Pro with Touch Bar.
 * iBridge T2 - found in the iMac Pro and later.

iBridge devices run a heavily modified version of watchOS, titled bridgeOS, and they drive functionality for a limited range of hardware components. They are currently only known to work with the Touch Bar and the built-in FaceTime HD camera.