  "mempoolminfee": 0.00000000

When the minrelaytxfee is > 0.

{
    if (request.fHelp || request.params.size() < 1 || request.params.size() > 2)
        throw std::runtime_error(
            "getblock \"blockhash\" ( verbosity ) \n"
            "\nIf verbosity is 0, returns a string that is serialized, hex-encoded data for block 'hash'.\n"
            "If verbosity is 1, returns an Object with information about block <hash>.\n"
            "If verbosity is 2, returns an Object with information about block <hash> and information about each transaction. \n"
            "\nArguments:\n"
            "1. \"blockhash\"          (string, required) The block hash\n"
            "2. verbosity              (numeric, optional, default=1) 0 for hex encoded data, 1 for a json object, and 2 for json object with transaction data\n"
            "\nResult (for verbosity = 0):\n"
            "\"data\"             (string) A string that is serialized, hex-encoded data for block 'hash'.\n"
            "\nResult (for verbosity = 1):\n"
            "{\n"
            "  \"hash\" : \"hash\",     (string) the block hash (same as provided)\n"
            "  \"confirmations\" : n,   (numeric) The number of confirmations, or -1 if the block is not on the main chain\n"
            "  \"size\" : n,            (numeric) The block size\n"
            "  \"strippedsize\" : n,    (numeric) The block size excluding witness data\n"
            "  \"weight\" : n           (numeric) The block weight as defined in BIP 141\n"
            "  \"height\" : n,          (numeric) The block height or index\n"