Link to [#20495](https://trac.torproject.org/projects/tor/ticket/20495) (meek blocked in China). Calling it "unknown" for now. ([diff](https://trac.torproject.org/projects/tor/wiki/doc/MetricsTimeline?action=diff&version=20)) URL: https://trac.torproject.org/projects/tor/wiki/doc/MetricsTimeline?version=20