Every .dk domain that delegates its _acme-challenge name to ef485161-abf7-4b7d-af23-137d4d9a49cc.16.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.