I am currently working on a project that is a spinoff (fork) from a framework I have been working on.
This project is intended to be pretty generic, but now I need to fork the codebase again for a client of mine.
At this moment, I have created a custom branch for my client, but I'd rather have a standalone repository for this.
Outline of the situation:
Note: when trying to 'fork a fork' in Github, you will receive a notification that you have already forked the project:
This is now very possible. You just go to the fork you want to fork and click "fork" like you would always do. This only works if you don't have a different fork of that repository in your account already, though. If you do, you have to delete it.
Answered in a comment by iFreilicht
Since this is the correct answer now, it is better to highlight it.