Every .dk domain whose www name is a CNAME to us6-a4e6f5b1-c7cf6b5a13de1e8a9a45176b8.pages.mailchi.mp, i.e. the website is hosted on that platform. A target that no longer exists is flagged as dangling. Data comes from our own scanners, which re-resolve every .dk domain in the zone roughly once a week.