Every .dk domain that delegates its _acme-challenge name to ac.39ba273a3c9da3ccb19a65cd0d5c028a.piccolomondo.dk.validate-akdv.net. Such CNAMEs hand DNS-01 certificate validation to a shared service, so this list shows who issues TLS certificates through it. Data comes from our own scanners, which re-resolve every .dk domain in the zone roughly once a week.