It is a standard of how one thing talks to another thing. It is JSON with some fingerprinting/hashing send over Websocket. Thats basically it. What you do with it, remains up to your implementation.
Thank you! Exactly this "It is JSON with some fingerprinting/hashing send over Websocket" should be write there somewhere + put a link to the documentation and an example of how to use it. I don't want to watch an hour-long video.