Any Windows. But the reason is that it appears on updated (unmodified) browsers, but not on a clean new 9.0a3. Old persistent settings of NoScript? Where to dig?
It looks fixed. The video plays in Tor Browser 9.0.4. It's also possible their site's admins changed something to fix it in the 7 months since this ticket was opened.
In Safer mode, I click once which pops up to allow MEDIA for /latest_version and then click again which pops up to allow MEDIA for /videoplayback. The yellow semi-transparent box doesn't tell you you have to click it a second time, so some users might think it doesn't work.
In Safest mode, I click once, and the video's direct link opens and fills the window. I click again, and the blue click-to-play pops-up. I allow MEDIA for /videoplayback and it plays.