Every .dk domain that delegates its _acme-challenge name to 71e641d4-8580-458f-81d0-66f2a4e66d04.auth.zigza.com. 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.