It was fixed, merged, and now in the latest release! It should now work normally.

This is a script written in Node.js to automatically disable auto-jump among other things in minecraft

This script is designed for MultiMC

Prerequisites: MultiMC: MultiMC/MultiMC5
Windows (I haven't tested this on any other os)
Node.JS
Familiarity with command prompt or powershell

Step 1: Download code

Step 2: Paste the Auto-MC-Config folder into your multimc root directory (The full path should look something like C:\Users\username\MultiMC\Auto-MC-Config)

Step 3: Open a terminal, navigate to the Auto-MC-Config folder, and run npm i to install the dependencies

Step 4: Open global settings in MultiMC (Not instance settings)

Step 5: Go to "Custom Commands"

Step 6: Put this in "startup script": node "../../../Auto-MC-Config/config.js"

Step 4: The script will now disable/enable specific settings each time you launch an instance. To cusomize those settings, use config.yaml in the Auto-MC-Config folder

• Why did you write this in Node?
  Because I like node

• Can you make this work for the official launcher?
  Maybe. If you find a way to make the default launcher run a script on startup of any installation, I can help you make the script work for it. However, my script depends on environment variables passed by MultiMC.