> db.hostInfo() { "system" : { "currentTime" : ISODate("2022-08-04T19:03:15.033Z"), "hostname" : "mylocalHostname:27503", "cpuAddrSize" : 64, "memSizeMB" : NumberLong(32768), "memLimitMB" : NumberLong(32768), "numCores" : 12, "cpuArch" : "x86_64", "numaEnabled" : false }, "os" : { "type" : "Darwin", "name" : "Mac OS X", "version" : "21.6.0" }, "extra" : { "extra" : { "versionString" : "Darwin Kernel Version 21.6.0: Sat Jun 18 17:07:25 PDT 2022; root:xnu-8020.140.41~1/RELEASE_X86_64", "alwaysFullSync" : 0, "nfsAsync" : 0, "model" : "MacBookPro15,1", "physicalCores" : 6, "cpuFrequencyMHz" : 2200, "cpuString" : "Intel(R) Core(TM) i7-8750H CPU @ 2.20GHz", "cpuFeatures" : "FPU VME DE PSE TSC MSR PAE MCE CX8 APIC SEP MTRR PGE MCA CMOV PAT PSE36 CLFSH DS ACPI MMX FXSR SSE SSE2 SS HTT TM PBE SSE3 PCLMULQDQ DTES64 MON DSCPL VMX EST TM2 SSSE3 FMA CX16 TPR PDCM SSE4.1 SSE4.2 x2APIC MOVBE POPCNT AES PCID XSAVE OSXSAVE SEGLIM64 TSCTMR AVX1.0 RDRAND F16C", "pageSize" : 4096, "scheduler" : "dualq" } }, "ok" : 1 } > db.version() 6.0.0-90-g89bc2f7
In MongoDB 5.1.1, 5.2.1 and 6.0.0 here and here, the HostInfoCmd command double-nests the 'extra' key as 'extra.extra'. This data also populates type 0 FTDC data chunks.