for Thunderbird 1.5.x/2.0.x / SeaMonkey 1.1.x on Mac OS X (Universal Binary)
enigmail-trunk-moz-darwin-x86-ppc-gecko18.xpi (build date: 2008-10-05, version: 0.96a.0+)

for Thunderbird Trunk / Seamonkey Trunk (Gecko 1.9) on Mac OS X (Universal Binary)
enigmail-trunk-tb-darwin-x86-ppc-trunk.xpi (build date: 2008-10-05, version: 0.96a.0+)