The option is used to re-wire foreign keys. The valid values are the names of data map components in the data map object. At run time, the source ID to destination ID mapping of the named data map component defines the foreign key mapping used by the data map field.
For example, when you copy from quote item to order item in a data map component Items, the hierarchical parent ID of a quote item cannot be literally copied to the order item parent ID. It needs to be re-wired to the corresponding order item ID. The ID mapping component must be Items, as the quote to order ID mapping is used to look up the order parent ID field using the value of the quote parent ID field.
For related information, see Configuring Event-Based Commands for DTU.