While some data is stored, no cookies are sent, plus there's heavy caching involved: "The result is that website visitors send very few requests to Google: We only see 1 CSS request per font family, per day, per browser."
All in all, those services (IIRC the JS library CDN is similar) don't seem to be designed to be a tracking data source except for some popularity stats about the data hosted there.
While some data is stored, no cookies are sent, plus there's heavy caching involved: "The result is that website visitors send very few requests to Google: We only see 1 CSS request per font family, per day, per browser."
All in all, those services (IIRC the JS library CDN is similar) don't seem to be designed to be a tracking data source except for some popularity stats about the data hosted there.