Say there is a youtube video I want to watch. In my config it is rendered in elinks then I go to it. I press my macro key which is the comma then a y to play the video in mpv with help from yt-dlp.

macro y set browser "i3 exec mpv" ; open-in-browser ; set browser "elinks %u"

If I want to open the video in my browser, I have the macro key + f:

macro f set browser "i3 exec firefox" ; open-in-browser ; set browser "elinks %u"

It is very extensible because I can map it exactly how I like. If I want to open it in any program, I just set a macro for it.