没看懂这个人说的啥意思？
After associating your GitHub and Unreal Engine accounts you should receive an email at the address used to sign up for Github inviting you to join the Epic Games Organization. You can follow the instructions in the email or, if you are logged into GitHub, you can goto this link (Epic Games · GitHub) and there should be a green Join button in the upper right of the page. Checking that Epic Games is listed in your GitHub profile as Moss suggested is another way to confirm that the Unreal Engine/Github account association was successful.
这个是链接地址：Souce code on github unavailable? - C++ - Epic Developer Community Forums