Is this true on firefox, as well? I use firefox.
Don't think so. I think the Firefox store has different rules and/or a different maintainer.
https://addons.mozilla.org/en-US/firefox/addon/stylish/revie...
https://addons.mozilla.org/en-US/firefox/addon/stylish/revie...
Here's a greasemonkey script I'm using: https://gist.github.com/Zren/8726ccca22659baaeb055fd0258df76...