This is simply the 64-bit counterpart of cefStatsPrefixQueries, counting FIB lookup queries for a given prefix length without wrapping as quickly as the 32-bit version. On a high-throughput core router doing millions of lookups per second, the 32-bit cefStatsPrefixQueries counter can wrap in minutes, so monitoring tools should poll this 64-bit object instead to get an accurate rate without correcting for frequent rollovers. A monitoring system polling every 5 minutes on a busy edge router would use this object to reliably compute queries-per-second for the /24 bucket without a wraparound miscalculation.