So, just for clarification: Jetpack currently let's you muck about with the DOM (I've watched the demo), but eventually it will let you mess around with Firefox

So, just for clarification: Jetpack currently let's you muck about with the DOM (I've watched the demo), but eventually it will let you mess around with Firefox itself? I've been thinking about writing a Firefox plugin to do something (seemingly) simple like show my HN Karma in the status bar (or anywhere in the "chrome" of Firefox, I guess). Is that the kind of thing I could do with Jetpack, or would I have to go the more traditional plugin route?