How does listenHTTP work internally? I understand it listens on the address you provide it in the HTTPServerSettings object, but what happens after?

I have been browsing a bit through the source code to end up in a dead end. I ended up at the listenHTTPPlain function, which to my understanding sets up the socket and starts listening on it using listenTCP. This function seems to do nothing but call itself though. How does that work?