CLEO (Compact Library Extension Organizer) is a Firefox extension that works with FEBE* to package any number of extensions/themes into an installable .xpi file.Why? Consider this: I, as an extension developer, have several different Firefox profiles. Whenever I start a new extension, I create a new profile for testing, debugging, etc. In this profile, I like to have a dozen or so developer related extensions installed. With CLEO, I can packaged all these extensions together into a single, installable xpi. You may have a list of your favorite extensions/themes that you would like to share with others. With CLEO, you can gather them all together into a single file (called, perhaps, \"My favorite extensions.xpi\") and post them on a webpage. Others can install the whole batch with a just a couple of clicks!