"The EXTEND_DATA segment is the child of EXTEND_HEADER segment. There will be 1 or more EXTEND_DATA segments per EXTEND_HEADER. It is not intended that the EXTEND_DATA include a file_item_nbr. Note that the data definition in this segment is for readability and not formatting. The EXTEND_DATA elements, ext_name and ext_value appear on the same line, the former as the XML field tag and the latter as the field value, in the EXTEND_HEADER segment. Each EXTEND_DATA segment may contain multiple rows of data that extend the applicable segment. "