I\'m looking for some guidance on how to replace requests for a specific javascript file with another file that I\'ll package with the Firefox addon.
See How can I implement a content converter in Firefox for all page elements? (its scope is much wider than what you really need -- read on) on how to use registerFactory to register a surrogate HTTP protocol handler, which can then instantiate channels with alternate (e.g. file:///...
-type) URIs when newChannel
is called with your particualr script's URI.