  "mempoolminfee": 0.00000000

When the minrelaytxfee is > 0.

{
    if (request.fHelp || request.params.size() != 1) {
        throw std::runtime_error(
            "getmempoolentry txid\n"
            "\nReturns mempool data for given transaction\n"
            "\nArguments:\n"
            "1. \"txid\"                   (string, required) The transaction id (must be in mempool)\n"
            "\nResult:\n"
            "{                           (json object)\n"
            + EntryDescriptionString()
            + "}\n"
            "\nExamples:\n"
            + HelpExampleCli("getmempoolentry", "\"mytxid\"")
            + HelpExampleRpc("getmempoolentry", "\"mytxid\"")
        );
    }
    uint256 hash = ParseHashV(request.params[0], "parameter 1");
    LOCK(mempool.cs);
    CTxMemPool::txiter it = mempool.mapTx.find(hash);
    if (it == mempool.mapTx.end()) {
        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Transaction not in mempool");
    }
    const CTxMemPoolEntry &e = *it;
    UniValue info(UniValue::VOBJ);
    entryToJSON(info, e);
    return info;
}
UniValue getblockhash(const JSONRPCRequest& request)