The ‘active’ thread is here:
But to specifically answer your question, it is designed to be headless. The “Start WebControl” is a button on the WebMCP application web page that you reach from whatever browser/computer you are using to talk to RPi. The address for WebMCP is xxx.xxx.xxx.xxx:5001. You can start/stop/update WebControl (which will be running on port 5000) from WebMCP. WebMCP will also report the python “print” statements similar to what you would see in the console when running groundcontrol.