matrix-spec/event-schemas/examples/m.room.third_party_invite

{
  "age": 242352,
  "content": {
    "display_name": "Alice Margatroid",
    "key_validity_url": "https://magic.forest/verifykey",
    "public_key": "abc123",
    "public_keys": [{
      "public_key": "def456",
      "key_validity_url": "https://magic.forest/verifykey"
    }]
  },
  "state_key": "pc98",
  "origin_server_ts": 1431961217939,
  "event_id": "$WLGTSEFSEF:localhost",
  "type": "m.room.third_party_invite",
  "room_id": "!Cuyf34gef24t:localhost",
  "sender": "@example:localhost"
}