Bug 1351363 is aiming to add as many apex/root Mozilla domains to the HSTS preload list as possible, to protect first connections and also to catch any subdomains that forget to set an HSTS header themselves. Rough steps: 1) Identify mozilla-releng.net subdomains that don't yet support HTTPS and file dependant bugs to fix them. 2) Ensure the apex/root domain (https://mozilla-releng.net/) serves an HSTS header that meets the requirements on https://hstspreload.org/ 3) Submit the domain using that same tool