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

JavaScript Toggle On and Off (WebExtension) – Get this Extension for 🦊 Firefox (en-US)

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

How to Install Extensions in Firefox

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

Let's Write a Web Extension - Mozilla Hacks - the Web developer blog

NoScript Add-On Updated for Firefox 57 and the New WebExtensions API

Quick Image Print – Get this Extension for 🦊 Firefox (en-CA)

WebExtensions in Firefox 48 Mozilla Add-ons Community Blog

Firefox: Event pages and unexpected property warnings on extension reload · Issue #384 · asciidoctor/asciidoctor-browser-extension · GitHub

Colors and Fonts Extractor on Indie Hackers

React Developer Tools – Get this Extension for 🦊 Firefox (en-US)

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

WebExtension X-Ray – Get this Extension for 🦊 Firefox (en-US)