It's a dropdown that filters which proposal statuses count toward proposal-based reports and totals. The options are: All Events, "Signed and Approved" Or "Fully Paid" Or "Partially Paid", "Fully Paid" Or "Partially Paid", and Only "Fully Paid". This same filter is applied everywhere the Catering Category Breakdown report pulls in proposal revenue — changing it changes what counts as "real" revenue there.