Every .dk domain that delegates its _acme-challenge name to c5f68905-5bfa-4efa-ba46-0c1d8f042eb8.13.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.