The page chrome://browser/content/browser.xhtml shows the whole Firefox UI, which you can use to work on your userChrome.css, and inspect with Dev Tools (rather than the Browse Toolbox in a separate w
How can I make the Browser Toolbox show in the same window as the browse rather than separate window?
Any way to disable automatic unloading of text & elements (virtual DOM / DOM unloading)? They break functionality like CTRL F
Can I make the titlebar or background completely transparent on macOS? (and no background blur, some Mac apps can disable that)