[BCP57]    Best Current Practice 57,
              <https://www.rfc-editor.org/info/bcp57>.
              At the time of writing, this BCP comprises the following:

              Haberman, B., Ed., "IANA Considerations for Internet Group
              Management Protocols", BCP 57, RFC 9778,
              DOI 10.17487/RFC9778, March 2025,
              <https://www.rfc-editor.org/info/rfc9778>.