It doesn't. The green line is for "None", meaning the test couldn't figure out which CMS was used. Many platforms now hide which CMS is being used, not to mention custom JS applications built with React and other frameworks/libraries would end up under "None" as well.
Which is different from "raw HTML". After all, everything the browser parses in the end is raw HTML, but this graph is about CMSs in particular.
Yes, that is how the survey works. None includes anything that can't be identified and raw html, too. That makes WordPress's achievement all the more impressive.
Which is different from "raw HTML". After all, everything the browser parses in the end is raw HTML, but this graph is about CMSs in particular.