Every .dk domain that delegates its _acme-challenge name to aab73e6e-0155-4119-9c69-a3ad6d6c265a.trustzonevalidation.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.