FXY 6-digit BUFR descriptor for Element (from Table B) or Operator (from Table C). 1 Schemata required to support WMO No. 306 Vol I.2 FM 94 BUFR (edition 4)- Manual on Codes; including definitions of structure and domain-specific metadata required to describe terms from WMO No. 306 Vol. 2014-09-03T09:53:14.486Z WMO No. 306 Vol FM 94 BUFR (edition 4) Reference value Reference value used when encoding the value of the BUFR Table B Element in WMO No. 306 Vol I.2 FM 94 BUFR. Scale Scale factor used when encoding the value of the BUFR Table B Element in WMO No. 306 Vol I.2 FM 94 BUFR. Data width (bits) Number of bits that are used when encoding the value of the BUFR Table B Element in WMO No. 306 Vol I.2 FM 94 BUFR.