Firefox 48.0 2 Mac 'link' Download Page

: For users on macOS 10.6 through 10.8, Firefox 45.9.0 ESR (Extended Support Release) is often recommended as a more secure alternative because it received security updates later than the 48.0.2 version. Download Information

If you cannot find a working or your system rejects it, consider these modern alternatives: Firefox 48.0 2 Mac Download