Identifier.system = "urn:ietf:rfc:3986" for domain names?

When Identifier.value is naturally a globally unique then Identifier.system element shall be set to “urn:ietf:rfc:3986”. Does that apply when the value is a fully qualified domain name like “”? The examples given are for OID and UUID so it wasn’t completely clear if domain names are also covered.

This issue came up in a discussion about mapping the HL7 V2 HD data type to FHIR. When the HD.3 component is set to “DNS” (from Table 0301), that indicates that the HD.2 component contains a fully qualified domain name.