TenFourFox is Mozilla Firefox 4 that runs on PPC Macs and OS X Tiger
If you have a G3, G4 or G5 Macintosh, or are stuck running Mac OS X 10.4 Tiger, you are unfortunately unable to run the latest version of Mozilla Firefox 4. Or are you? TenFourFox is basically Firefox 4 that runs on the older Macs and OS versions, bringing all the modern browser goodness to Mac users stuck in the past.
Atlease someone took the time to retune something out of firefox 4 and made it into tenfourfox for ppc users.