Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you have been placed in read-only mode.
Please download a browser that supports JavaScript, or enable it if it's disabled (i.e. NoScript).
Do not install it from the marketplace, you need version 4.0.4 which is not the one there.
You need to download it from Modrinth and place it in .minecraft/libraries/me/deftware/EMC-F-v2/latest-1.21.4/