It's a referenced element. For detailed description, please refer referenced element doc. Fulfillment order reverse reverse pick update/modification detailed information Fulfillment order reverse pick identifier Collection of reverse pick line items representing modified information Collection of custom attributes to be updated for the fulfillment order reverse pick. Fulfillment order reverse reverse pick update/modification line item information Identifier of the fulfillment order line item corresponding to the created reverse pick line item Quantity in standard unit of measure. This type can hold a number of digits count 12. This type can hold a number of digits count 20 and fraction digit count of 4.