The github link still works. If you’re getting a 404 page it’s because that’s what Github shows when you don’t have access to the private repository you’re trying to view. (EpicGames/UnrealEngine). That results from either a) not being logged in, or b) not associating your github account with your unreal account yet.
Also the link, links to a PR, which you can look at if you want to modify your code to match, but I just went to’s repo and cloned it @ https://github.com/ArneBezuijen/UnrealEngine/tree/master (you’ll still hit 404 on for all the same reasons as Unreal, but resolve it in the same manner).