EDITED 2019-02-08

`maxTxFee` is a global variable, used by both the raw transaction and wallet RPCs. It's set from `-maxtxfee`.

~listed in the global help text in init.cpp, but is only set in `WalletInit::ParameterInteraction()`. If the wallet is disabled, then `-maxtxfee` is ignored and the default is used.~

~This behaviour has existed since the mempool was changed to limit acceptance based on `maxTxFee` in https://github.com/bitcoin/bitcoin/commit/fa331db68bcc68e4c93fb45aaa30f911b0ecfe1a.~

~Short-term fix is to move the `-maxtxfee` handling to `InitParameterInteraction()` in init.cpp.~
EDIT: `maxTxFee` initiation bug fixed in #15357 

I don't think we should share this setting between the node and wallet.
#if defined(HAVE_CONFIG_H)
#include <config/bitcoin-config.h>
#endif
#include <init.h>
#include <addrman.h>
#include <amount.h>
#include <banman.h>
#include <chain.h>
#include <chainparams.h>
#include <checkpoints.h>
#include <compat/sanity.h>
#include <consensus/validation.h>
#include <fs.h>
#include <httpserver.h>
#include <httprpc.h>
#include <interfaces/chain.h>
#include <index/txindex.h>
#include <key.h>
#include <validation.h>
#include <miner.h>