TenFourFox is a free and open-source web browser based on Firefox. Its unique selling point is that it[SQ]s designed to run on older PowerPC-based Macs running Mac OS X 10.4 (Tiger) through 10.5 (Leopard). These operating systems are no longer officially supported by Mozilla, and modern browsers like Firefox won[SQ]t work on them.

Essentially, TenFourFox provides a way for users of these aging Macs to continue accessing the internet with a relatively modern browsing experience, albeit one with limitations compared to current browsers. It[SQ]s a community-maintained project, so it[SQ]s not as polished or feature-rich as the official Firefox releases, but it[SQ]s a valuable resource for those who want to keep their older hardware functional.