Bug 533038 made it so extensions don't need to be extracted from their .xpi files. But extensions with binary components still need to be unpacked, since these components can't be loaded from within an archive. However, bug 588607 implemented a custom dlopen() allowing binary libraries to be loaded from a .apk on Android. If this can be adapted to work on all OSes, then (most) extensions with binary components won't need to be unpacked either.
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