The client ID
OK
ISO 3166-1 alpha-2 country code (e.g. "US", "GB"). Defaults to clinic's region if null.
A client's secondary (backup) emergency contact — free-text, same shape as the primary one (PAW-650). Backed by the SecondaryEmergencyContact* columns on the client.
Marketing attribution — "how did you hear about us". Staff/client entered.
Read-only provenance — the channel that created the record (ITE-419).