Every .dk domain that delegates its _acme-challenge name to 196b8e6f-0917-4645-979c-9e5d922fb762.auth.acme-challenge.dk. 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.