Se você estiver usando o Firefox / SeaMonkey, tente usar a extensão Formato do arquivo do Mozilla , que deve funcionar em um Mac de acordo com a página de instalação:
Mozilla Archive Format, at the time of each release, is tested and verified with the most recent browser versions available in the following release channels:
Firefox 3.6 Firefox Beta Firefox Release SeaMonkey 2.1
Testing is done under Windows XP, but the add-on is expected to work on all the platforms supported by the browser. Note that the add-on is only declared compatible with versions of Firefox and SeaMonkey on which it is actually tested, thus excluding the Nightly channel, though partial compatibility might be implemented for the Aurora channel. Users that would like to experiment with using the add-on on the Nightly or Aurora channels should override the compatibility declarations using the Add-on Compatibility Reporter.