For Raspberry Pi datafeed subscription you can use this:
nud setdatafeed https://raw.githubusercontent.com/cryptog/nu_data_feed/master/cryptog_nu_data_feed.json https://raw.githubusercontent.com/cryptog/nu_data_feed/master/cryptog_nu_data_feed.json.signature SSmCygqYLTmzaQwL2i7ScryVdsdjK2hhgV