Firefox ESR is described as 'Mozilla Firefox Extended Support Release is a community-led project that allows organizations to benefit from the speed, flexibility and security of Firefox while getting the support they need' and is a Web Browser in the web browsers category. There are more than 50 alternatives to Firefox ESR for a variety of platforms, including Windows, Mac, Linux, Android and Android Tablet apps. The best Firefox ESR alternative is Mozilla Firefox, which is both free and Open Source. Other great apps like Firefox ESR are Brave, Chromium, Mullvad Browser and ungoogled-chromium.