The back of the Nest display has two ports: a micro USB port that can be used for charging (and possibly hacking the Nest's software), and a proprietary 20-pin connector that fits onto the base unit's matching plug.

Removing a few screws allows us to separate the Nest display's rear panel from the rest of the unit and continue our exploration.

We'd like to point out that these screws can in fact be removed with the included driver. Way to make your product's internals accessible, Nest!