Time to get a look at that mystery chip! With a little help from our friends at TechInsights, we get a peek under the shields on the back of the display and find:

A Broadcom touch screen controller, labeled BCM15951B0KUB2G.

Also along for the ride: a new STMicro device we have not seen before, an OLED PMIC labeled 10 THADT733 X-139U.