[johschmitz]

The control messages are transmitted via CAN bus

https://en.wikipedia.org/wiki/CAN_bus

The exact message content and protocols are reverse engineered.

Some cars use FlexRay instead of CAN bus but that has only experimental support.

[grepfru_it]

Flexray is supported only on Audi on a specific Flexray-canbus integration board that was just end of lifed and Comma has no desire to support other boards. It was a proof of concept for anyone wishing to implement the same