Great addon that does exactly what it needs to, but it would have gotten 5 stars if it had a Firefox keyboard shortcut to play the current URL (read: tab).

Only thing that's missing.

works well with mpv player. gave it a four because some Telesur videos do not play. They have different aspect ratio. Example is https://www.youtube.com/watch?v=jbSED1r9W-Q. If I try to manually run mpv on the tmp file that it creates, mpv does not start.
I can download this video with youtube-dl in terminal and play it directly to mpv no problem.
Here is the output if I manually play the EXTM3U file from terminal.

$ mpv /tmp/mozilla_buster0/rqIjNeCd
Playing: /tmp/mozilla_buster0/rqIjNeCd
Playing: https://www.youtube.com/watch?v=jbSED1r9W-Q
Refusing to load potentially unsafe URL from a playlist.
Use --playlist=file or the --load-unsafe-playlists option to load it anyway.
Exiting... (Some errors happened)

If I directly play the http from file i get it works and I get

$ mpv https://www.youtube.com/watch?v=jbSED1r9W-Q
Playing: https://www.youtube.com/watch?v=jbSED1r9W-Q
[mkv] Unexpected end of file (no clusters found)
(+) Video --vid=1 (*) (vp9 1080x1080 29.970fps)
(+) Audio --aid=1 --alang=eng (*) 'DASH audio' (aac 2ch 44100Hz) (external)
AO: [pulse] 44100Hz stereo 2ch float
[ffmpeg/video] vp9: No support for codec vp9 profile 0.
[ffmpeg/video] vp9: Failed setup for format vaapi_vld: hwaccel initialisation returned error.
VO: [gpu] 1080x1080 yuv420p
AV: 00:00:06 / 00:01:22 (7%) A-V: 0.000 Cache: 57s+8MB
[ffmpeg] tls: Error decoding the received TLS packet.
Exiting... (Quit)