Hi Alexander,
you are right it seems the installer is not installing the Blender-Addon at all, even it is enabled in the installer (see attached image).
Yes I have the file you mentioned, and the path to Blender Addons I never changed, it is the original one provided by Blender’s native installation procedure.
It seems there are two places of addons-directory:
1.:
C:\Users\MyUsername\AppData\Roaming\Blender Foundation\Blender\2.82\scripts\addons
(this one contains only one folder called ‘forgotten_tools’)
2.:
C:\Program Files\Blender Foundation\Blender 2.82\2.82\scripts\addons
(this one contains lots of folders and *.py files)