What does XMODIFIERS="@im=null" do exactly?

I use a script including this line for launching Minecraft to fix an annoying keyboard control bug, I found it in the comments of the bug report page here. I was just happy to find a solution back then, but now I'm starting to wonder what this line actually does. The closesed thing I could find were posts about "@im=ibus" which doesn't seem to explain much about my question, and "XMODIFIERS" obviously changes something with how Xserver handles input, I'm lost on what "export" means.

This is what the scripts looks like
Code:#!/bin/bash
export XMODIFIERS="@im=null"
flatpak run com.mojang.MinecraftYeah, so anyone know what this script is doing that's working around the bug? Thanks.