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://greasyfork.org/scripts/429557-gmrequirechecker/code/GMRequireChecker.js?version=951692
A simple script to check whether
if it works, then you can get variable
GMRequiredJSLoaded which equals to true. Otherwise,
GMRequiredJSLoaded will just not exist.
You can also use this script to check whether your script is running in a non-ScriptManager-environment.