In the item ledger entries (page 38) there is the column "Order Number" (Order No., field no. 91) this only displays the order numbers for actual reports, consumption and stock transfers. Sales delivery order numbers are not displayed, but they have a order no. For user it is not plausible that the delivery orders have in the column "Order No" has no order number.

The tooltip say also that in this column "specifies the number of the order thtat created the entry".