Firefox 4 won’t run on X Tiger 10.4, Mozilla abandoned that platform. I wonder how much Apple paid them for that?
Apple probably didn’t pay them a penny. Eventually developers only write code for the newer versions of operating systems. Hexwar, the little Scottish company that redoes old 70’s vintage hexgrid wargames as computer-rendered games played by an online variant of play-by-post, dropped support for OS 10.4 and for a few old small-market-share versions of Windows last year. I’m sure they’re so small they wouldn’t rate a bribe from Apple or Microsoft. Continuing support for older small-market-share operating systems just turns out to be uneconomical (yes, even for a huge non-profit like Mozilla).