This field shows the source type that applies to the source number that is shown in the Source No. field.
The program fills in the field based one the following principles:
If the entry was posted from an item journal line, the field is blank.
If the entry was posted from a sales line, the source type is Customer.
If it was posted from a purchase line, the source type is Vendor.
If the entry resulted from the production of a BOM (bill of materials), the source type is Item.