Under this status you will see items which templates status was set to Hidden (not active or discontinued), it means that this item is currently not active / not available for sale or discontinued.
Depending on the products you sell, you may have large quantities in stock during certain time of the year and low stock or no stock at all during another time.
Examples of seasonal items:
etc
Once these items are in demand again - simply change template status to "Active" and prepare a new shipment to be sent to eWarehouse.