The desc explicitly states this is the number of connections deleted by SecureXL, a cumulative counter since startup. Added minus deleted should track closely with fwSXLConnsExisting; a persistent gap between that arithmetic and the reported existing count can indicate a SecureXL table cleanup problem worth investigating before the connection table fills up. e.g. added and deleted counters both near 5 million and staying roughly in sync is healthy, versus deleted noticeably lagging behind added over time.