Hi @B3b3L, welcome to the GitHub Support Community! If you believe there should be a repository there but you’re seeing a 404 instead this usually means you don’t have permission to see it. GitHub isn’t able to grant permissions for things like this so you’ll need to contact the repository owner.
It looks like Epic Games has specific instructions on how to join their GitHub organization and gain access at the link below so I’d make sure you’ve followed the steps in this article:
Unreal Engine 4 on Github
Unreal Engine is the world’s most open and advanced real-time 3D creation platform for photoreal visuals and immersive experiences.