Replacing the circuit board with a custom one wasn't a hugely difficult process. 603 SMD components were mainly used to keep the size down to fit in such a limited space.
The position the dial is at is dictated by a resistance wheel. Each segment adds 220Ohms of resistance and checking this value using the internal voltage of the chip gives sufficient deviation to identify each position.
The WS2812b is included on the board and if the central dial is translucent the dial will glow.