Well, on second look it seems like the mast is using <video> for me as well- I originally looked too far and thought the id "fbhome-cinemagraph-canary" led to an animated gif. Apologies on making the wrong call!
Also, as a previous reply pointed out, what they're doing really doesn't count as a cinemagraph- FB needs to stop butchering words.
Also, as a previous reply pointed out, what they're doing really doesn't count as a cinemagraph- FB needs to stop butchering words.