Every .dk domain that delegates its _acme-challenge name to 1a89f7cb-54e6-42b8-8ca9-bb4bcf8ea7b5.auth.acme-dns.io. 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.