User blog comment:Brandon Rhea/How we're testing the fandom.com domain migration/@comment-34687312-20181015145418/@comment-27345308-20181016185755

They already have an HTTPS certificate covering subdomains. What they can't do is add an HTTPS certificate covering, so language wikis are not currently served over HTTPS. The migration to fandom.com is at the same time the migration of URLs for language wikis to contain language codes in their article path, and those are two things being worked on separately, so the migrated communities will get to be testing points for both fandom.com migration and HTTPS support on double-subdomain wikis.