In reply to Chris Aldrich.

@chrisaldrich I tested a bit more (I'm not blind or keyboard-only, so I was a bit quick to test for lack of time).I can play/pause, fast forward/back with my keyboard on Firefox natively.I expected to be able to cycle through the controls (hence my initial remark), so was surprised to have to tab into → interact with space bar, left/right arrows → tab out.It works pretty well, the only thing I can't seem to do is set the volume, although I can do it system-wide.