I've built a functional extension prototype for the user following feature.
Basically this extension is composed with the code from fof/follow-tags and fof/ignored-users. This is my first time making Flarum extension and using the new Laravel API, so it could really need some improvement.
Currently the extension only works on new discussions (no notifications on replies yet).
Warning: Do not use in production.
composer require simonxeko/follow-users