Unfortunately I had to remove the UnityDecompiled repo due to a request from Unity's legal team.
If you'd like to decompile Unity yourself, find your local UnityEditor.dll and decompile it using either ILSpy or dotPeek - it's easy!
Thanks to the community for all of your contributions over the past three years, it was a great resource while it lasted!
-Matt
UPDATE: Unity has now released an official repo of their C# source code!