I created a Nostr event type to represent a Registered Relay User. It's published by the admin pubkey of the relay itself (NIP-11). It means the relay recognizes the user as having an account, possibly granting it special privileges, and granting it a NIP-05 on the relay's domain.

{
"id": "d6ae2f320ae163612bf28080e7c6e55b228ee39bfa04ad50baab2e51022d4d59",
"kind": 30361,
"pubkey": "4cfc6ceb07bbe2f5e75f746f3e6f0eda53973e0374cd6bdbce7a930e10437e06",
"content": "",
"created_at": 1691568245,
"tags": [
["d", "79c2cae114ea28a981e7559b4fe7854a473521a8d22a66bbab9fa248eb820ff6"],
["name", "alex"],
["role", "user"],
["origin", "https://ditto.ngrok.app"],
["alt", "@alex@ditto.ngrok.app's account was updated by the admins of ditto.ngrok.app"]
],
"sig": "fc12db77b1c8f8aa86c73b617f0cd4af1e6ba244239eaf3164a292de6d39363f32d6b817ffff796ace7a103d75e1d8e6a0fb7f618819b32d81a953b4a75d7507"
}