https://www.ghacks.net/2019/05/24/firefox-69-userchrome-css-and-usercontent-css-disabled-by-default/Mozilla plans to land a change in Firefox 69 that disables the loading of userChrome.css and userContent.css by default to improve performance.
https://www.ghacks.net/2019/05/24/firefox-69-userchrome-css-and-usercontent-css-disabled-by-default/Mozilla plans to land a change in Firefox 69 that disables the loading of userChrome.css and userContent.css by default to improve performance.