Every .dk domain that delegates its _acme-challenge name to b985b9ef-d673-43b1-b77e-7bc8c393fd8d.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.