Tried 2.8.0 - 2.8.7. None of them work consistently.
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The new version works for a day, then fails to detect any link. Reinstalling the addon and restaing Firefox make it work again, but only briefly. And I have to set up the customized command each time. I also need to ask it to detect direct links, or nothing shows up.
Also, when it is working, it detects way too many clips. The new clips are added to the top one by one, so the m3u8 link keeps moving down and is difficult to click. I suggest to add newly found links to the bottom. It also seems to ignore the "This tab"/"All tabs" settings and shows all.

When it worked, it was absolutely fantastic! I use it together with ffmpeg, but with user-command.