User blog comment:Brandon Rhea/How we're testing the fandom.com domain migration/@comment-28083312-20180928054231/@comment-31955138-20180928080910

I beleive what they mean is that it will use HTTPS for everyone including for web spiders. This will cause the search engines to realise that the site is avalible over HTTPS and so they will rank it higher. Hence this test appears to be biased.