[wlug] “You must enable DRM to play some audio or video on this page.”

I have seen Firefox give me this message that I need to “enable DRM” (i.e. install support for Encrypted Media Extensions) when I visit certain pages. One site that is currently triggering this for me is Metservice <https://www.metservice.com/towns-cities/locations/hamilton>. Yet I can’t see anything on that page that I might be blocked from playing. There is a Video Forecast clip, but I seem to be able to play that OK. Anybody else get this message?