You will need to install a user script manager extension to install this script.
This script should not be not be installed directly. It is a library for other scripts to include with the meta directive
// @require https://update.greasyfork.org/scripts/372917/639024/gmxhr-fetch.js
A fetch-like polyfill for userscript managers.(TM,GM,VM)
Add the following content into your script's metablock.
// @require https://unpkg.com/gmxhr-fetch // @grant GM_xmlhttpRequest // @grant GM.xmlHttpRequest
Then you can call
gmfetch anywhere in the script just like