Localization (L10n) is the process of translating software user interfaces from one language to another and adapting it to suit a foreign culture. These resources are for anyone with an interest in the technical aspects involved in localization. They are for developers and all contributors.
To localize the description of an extension (the string that shows up under extension's name in the Extensions window), you need to use a special preference key to override the description specified in your install.rdf file. This article contains instructions on how to modify this preference key.