Every .dk domain that delegates its _acme-challenge name to 66c2c6ab-877d-429f-bae6-4be0abc40e9b.12.authorize.certificatemanager.goog. 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.