CLEO – Get this Extension for 🦊 Firefox (ja)Firefox v57 notice: CLEO is considered a 'legacy' extension and will no longer work with Firefox v57 and above. CLEO cannot be written with the WebExtensions platform that Mozilla has adopted for all extensions. CLEO will still be maintained, but only for Firefox clones (like Pale Moon). CLEO allows you to organize individual extensions/themes by combining them together into a single, installable
