Just install it and then go to the user data directory .....
http://www.chromium.org/user-experience/user-data-directory
then to the profile directory that you installed it, then the extensions directory, and then the directory with the key of your extension, then the directory with the latest version and you will find all your files. You can find the key indicated on the extension page in chrome in developer mode. Remember to change the manifest, remove the update URL, etc.
Or if you are on windows (I know that it works in XP, never tested vista / 7), you can use my convenient ExtensionOpener tool .....
http://forum.valorsolo.com/viewtopic.php?f=35&t=269&p=1163
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