Mozilla Firefox
Mozilla Firefox is a free and open-source web browser developed by the Mozilla Foundation. It provides a fast, secure, and customizable browsing experience with features like tabbed browsing, privacy tools, and extensive add-on support. Firefox is cross-platform, running on Windows, macOS, Linux, and mobile operating systems.
Developers should learn Firefox for web development testing to ensure cross-browser compatibility, as it is a major browser with a significant user base. It is particularly useful for debugging with built-in developer tools, testing privacy-focused features, and developing extensions using its WebExtensions API. Firefox's open-source nature also makes it valuable for contributing to browser technology or customizing for specific projects.