Understanding how mblock serial 2G connect work?


After understanding how the Bluetooth connection work using mBot and successfully communicationg mBot using Bluetooth HC-05 and Arduino, I want to understand how Serial 2.4G connection work.

I can see that mBot uses esp8266, however I am not able to understand what is the USB device that is connected to PC for connecting to esp8266.

I am trying to use mBlock in a school where I can’t afford many makeblock kits and hence want to use simple arduino kit with wifi using mBlock.

I looked at the mblock code to understand what does Serial 2.4G does. To my surprise the code is commented. I am not sure if I am looking at the right stuff.