One TURN server per line: turn:host:port username password, a JSON iceServers array, or an https URL that returns one. When this page is served from its own server the default is that server's /turn-creds endpoint, which hands out short-lived credentials for the relay that runs next to the game. With Hide my IP on, your browser only offers TURN relay candidates (iceTransportPolicy: 'relay'), so other players only ever see the relay's address, never yours. The server browser itself is just notes on the signalling relays — nobody connects to you until they join. Signalling goes through public Nostr relays (they see your IP like any website would; other players don't). Use the test button after changing anything.