We do our best to support Firefox's latest Extended Support Release (ESR). Older versions of Firefox may disable some features on GitHub and require the latest version of Firefox.
You may encounter unexpected bugs in beta and developer builds of our supported browsers. If you encounter a bug on GitHub in one of these unreleased builds, please verify that it also exists in the stable version of the same browser. If the bug only exists in the unstable version, consider reporting the bug to the browser developer.