Just to add to what @qu1ck said, the default path for plugins in windows (the folder where they should be saved) is:
%appdata%/kicad/scripting/plugins
(in my computer that means: C:\Users\user\AppData\Roaming\KiCad_v5_1_7\scripting\plugins )
the location:
C:\Program Files\KiCad_v5_1_7\share\kicad\scripting\plugins
or wherever kicad got installed, it is not meant for user plugins, those python files are part of the kicad installation and are used for creating footprints with the wizards or any other useful stuff.