well known files suck dih but quite simple

serve under /.well-known/matrix/client under domainroot
{
  "m.homeserver": {
    "base_url": "https://terrorist.academy"
  },
  "org.matrix.msc4143.rtc_foci": [
    {
      "type": "livekit",
      "livekit_service_url": "https://jwt.matrixrtc.terrorist.academy"
    }
  ],
  "org.matrix.msc3575.proxy": {
    "url": "https://matrixrtc.terrorist.academy"
  }
}

serve under .well-known/element/element.json same thing