Find Hidden Web Directories - Fuzz URLs with ffuf
Web servers often have secret directories, not linked from anywhere.
You could find them by trying different paths manually: /secret, /.svn /admin. This article shows you how fuff can do this to you automatically.
For practice, I coded a target that you can run locally, without Internet. I will also tell you the solution, so you can test your environment. As bonus, there is a challenge target where you can find to solution yourself.