Earlier quoted context omitted.
I find it incredibly useful to be able to toggle styles on and off in a simple GUI, especially for these two simple global styles: video { /* flip video horizontally */ transform: scaleX(-1) !important; } or /** scale videos that were originally 4:3, but were encoded as 16:9 into proper 4:3 again */ video { transform: scaleX(0.75) !important; } It's not extremely useful, but every time I toggle them on, I'm very happ…
Out of curiosity, what do you use the first flip horizontally style for?
To flip videos that have been flipped, or for watching a video in the mirror. Maybe it's 1 in 100 videos, or even less, but it's so nice to be able to just toggle a button that flips the video properly.