In June, Mozilla had announced that they were performing a limited Shield study for their Nightly users to monitor the performance of DNS-over-HTTPS (DoH) in Firefox. This study uses Cloudflare’s DNS service to encrypt both the requests and responses to any DNS queries in order to increase a user’s privacy. […]

from https://www.bleepingcomputer.com/news/software/mozilla-firefox-expands-dns-over-https-doh-test-to-release-channel/