From this point on it will not be necessary to maintain Mac OS X 10.4
support in Gecko 1.9.3 (mozilla-central). We will be performing
related cleanup soon.
This does not affect current users of Firefox, or updates to Firefox
3.6: Mac OS X 10.4 will continue to be supported via Firefox 3.6 until
its end-of-life (not yet scheduled).
Thanks to everyone who provided input on this issue. We believe a Mac
OS X 10.5 minimum will allow us to provide the best experience
possible to our users.