When I used Windows many years ago the browser I used was Opera.
When I moved to Linux I installed Opera and everything worked fine except from videos on certain websites like the BBC. Some YouTube videos were also affected. I simply received the message that Flash was not installed, even though it was. I switched over to Firefox and the videos played without problem. I was baffled. In the end I grudgingly stuck with Firefox.
It was only a few months ago that I heard of the libffmpeg.so requirement. It was only after finding this out that I found numerous forum posts all over the web wondering what's wrong with video playback on Chromium based browsers. This is a significant problem, and its solution is not obvious.
The above mentioned methods of installing the files into browsers is the first time I've seen a simple way of addressing the problem - enter text in terminal, enter password, file installed, life has one less problem
What I was suggesting with my earlier poor attempt at demonstrating code is that a second button is placed on the MX codec installer. It is marked something like "Enable Flash in Opera, Vivaldi and Slimjet". When the button is clicked a script checks which browser(s) is installed, and it then runs the code to install libffmpeg.so for this / these browser(s). The installation details could be displayed in the terminal.
This would save newbies a lot of head scratching, and it would be incredibly convenient for anyone wanting to update an already installed libffmpeg.so.
I hope this makes sense.