Mozilla Firefox is a free, open-source and cross-platform web browser for Windows, Linux, MacOS X and many other operating systems. It is fast and easy to use, and offers many advantages over other web browsers, such as tabbed browsing and the ability to block pop-up windows. Firefox also offers excellent bookmark and history management, and it can be extended by developers using industry standards such as XML, CSS, JavaScript, C++, etc. Many extensions are available. This package provides Firefox 52 ESR. It is now unsupported and is provided only for platforms where the Rust toolchain required in newer Firefox versions is problematic. Note: Due to upstream's trademark policies, this package identifies as "Nightly" rather than "Firefox" by default.