This WebRTC demonstration operates without a STUN server or signaling server, showcasing a simplified peer-to-peer connection. To observe the connection process in detail, open your browser's developer tools (press F12) and monitor the console output. In this setup, Peer 1 initiates the connection, while Peer 2 responds. The entire negotiation occurs in-band, meaning all necessary information is exchanged directly between the peers without requiring any external coordination or out-of-band communication.
You will need to find a way to share the offer with the peer. This is where a signalling server can be used.