Just tried it. Didn't work. First off the only options are "default", "no user gesture required", "user gesture is required for cross-origin iframes", "Document

Just tried it. Didn't work. First off the only options are "default", "no user gesture required", "user gesture is required for cross-origin iframes", "Document user activation is required". None of which sounds like "disable autoplay" Set the flag to "Document user activation is required", restarted browser, went to youtube, videos autoplay