This is root element of this document which contains name space definitions for the document elements. It's a referenced element. For detailed description, please refer referenced element doc. Description is not available. Contains the value of the differential group that the differential belongs to. This field must be a valid value on the diff_group_head table. Contains the value of the differential that is included in the differential group. This field must be a valid value from the diff_ids table. Provide an extension hook to customize DiffGrpDtlRef. This type can hold a string of max length of 10 characters.