Font Inspector (WebExtension) – Get this Extension for 🦊 Firefox (en-US)

Download Font Inspector (WebExtension) for Firefox. Click on any element to get the font info in a page popup

MobiDevTools – Get this Extension for 🦊 Firefox Android (en-US)

Form History Control – Get this Extension for 🦊 Firefox (en-US)

Context Search Origin – Get this Extension for 🦊 Firefox (en-US)

Weh Inspector – Get this Extension for 🦊 Firefox (en-US)

Laboratory (Content Security Policy / CSP Toolkit) – Get this Extension for 🦊 Firefox (en-US)

Tree Style Tab For Chrome

WebExtensions in Firefox 48 Mozilla Add-ons Community Blog

Open in PDF Viewer – Get this Extension for 🦊 Firefox (en-US)

Copy Link Extras – Get this Extension for 🦊 Firefox (en-US)

SmartProxy – Get this Extension for 🦊 Firefox (en-US)

Extension source viewer – Get this Extension for 🦊 Firefox (en-US)

Not all colours will work - Twine - The Interactive Fiction Community Forum