Our website provided a free download of MultiFirefox 2.3.3 for Mac. The application lies within Internet & Network Tools, more precisely Browsers. This free Mac app was originally created by com.CodeContortionist.
From the developer:
MultiFirefox... With multiple versions of appropriately renamed Firefox instances in your Applications folder (i.e., Firefox2, Firefox3), this launcher will allow you to launch any version of Firefox along with a matched version profile. Further, this launcher also allows you to run all of these versions of Firefox side-by-side.
You may want to check out more software for Mac, such as Firefox 4, wwwDOT! Web Browser or Citrio, which might be related to MultiFirefox.