A browser or a machine hosts the server, everyone else joins it.
A machine host is reached over WebTransport; a browser host has no address to
connect to, so those go peer-to-peer over WebRTC — which is also where a
WebTransport attempt lands when it fails, relayed by Cloudflare TURN when
networks are hostile.
Settings
Host a game
⚠️
Keep this tab focused while hosting.
Browsers throttle background tabs — if the host tab loses focus,
the match lags for everyone on the server.