I am looking for a map of polish 'powiaty', eng. 'county' or 'district' (i.e. second-level unit of local government and administration in Poland, equivalent to a county, district or prefecture) in JSON.
You can find shapefiles here: https://gis-support.pl/granice-administracyjne/. I need a JSON to be able to use it in PowerBI as a custom map.
And possibly if you have some ideas is there any online available repository which offers numerous JSON files for different countries to download?