My original intent was to customize firefox with userChrome.js scripts. However /defaults/pref directory is nowhere to be found. Tested on both apple silicone and intel macs running macos sequoia 15.3, firefox 135. Custom userChrome.css files are in use but I don't think it matters. I did use browser console to find and recheck file directories. Going through every folder in both firefox.app/contents and /Users/(myname)/Library/Application Support/Firefox/ showed nothing. Show hidden files are turned on, and the following commands via terminal showed no valid responses. sudo open /Applications/Firefox.app/Contents/Resources/defaults/pref open /Applications/Firefox.app/Contents/Resources/defaults/pref cd /Applications/Firefox.app/Contents/Resources ls -la cd defaults ls -la cd pref ls -la find /Applications/Firefox.app -name "pref" 2>/dev/null