Rated 3 out of 5 stars

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Unfortunately, it doesn't work on G3 with Mac OS X 10.4.9 and Firefox 3.0.3.

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This review is for a previous version of the add-on (1.0b1). 

Do you get an error? Does it load? If you have any more details, you could file an issues at http://code.google.com/p/mozilla-keychain/issues

It *should* be working on 10.4.* and on Firefox 3.0.* because I did make sure to compile against the old libraries, but I don't actually have 10.4 to test with on a regular basis.