Customers who add a new data attribute (e.g. a SELECT field like "Classification" on a ticket type) to a board with existing tickets cannot backfill it. Needs: (1) a "not set / is empty" filter option for data attributes on boards and in the inbox, so unclassified tickets can be isolated; (2) a bulk action to set a data attribute value on all selected tickets. Today the bulk bar only offers Archive, Close, Snooze, Assign, Team, Priority and Tag, and the attribute filter only lists declared choices. Use case: 200+ existing tickets that need a Classification value without opening each one.