In Safari on OS X, Facebook does use the native <video> player. I'm guessing that Facebook encodes video h264 which isn't natively supported in Firefox; rather it relies on support in the operating system. I'm not sure…
I'm pretty sure it's Paper by 53, more information is available here: https://www.fiftythree.com/paper. If you look at some of the screenshots on the site, you might notice some similarities.
In Safari on OS X, Facebook does use the native <video> player. I'm guessing that Facebook encodes video h264 which isn't natively supported in Firefox; rather it relies on support in the operating system. I'm not sure…
I'm pretty sure it's Paper by 53, more information is available here: https://www.fiftythree.com/paper. If you look at some of the screenshots on the site, you might notice some similarities.