This is the 64-bit version of cefStatsPrefixElements, giving the current count of FIB entries for a given prefix length on platforms whose FIB is large enough to need a wider counter. On very large-scale routers carrying a full Internet table plus VPN or VRF routes, capacity-planning tools should read this object to accurately size FIB TCAM usage. A service-provider router carrying 900,000-plus IPv4 routes would report the bulk of this count concentrated in the /24 bucket, reflecting typical Internet route aggregation.