By default, the following the current installation instructions simply leads to a paste of the contents of this repo inside the user-storage addons folder, which is not ideal for organising addons. If you have cloned the repo elsewhere, it won't even copy all the contents, just the __init__.py script.
If one decides to clone the repository (which should be the best way to use this fantastic project), the ideal way is to do so directly in the addons folder location. For Windows users, it's C:\Users\<USERNAME>\AppData\Roaming\Blender Foundation\Blender\<MAJOR_VERSION>.<MINOR_VERSION>\scripts\addons.