... Chapter 6. Packaging and Installing Applications- P2 6.2.3.4. Overlaying Mozilla files into your application In the previous section, we ... package manifest it can read and a package type that doesn't break the security boundary for applications (i.e., a new theme, a new language pack, or new content that doesn't use XPConnect), ... several times in this book. It plays an important (but sometimes invisible) role in the way Mozilla applications, including the Mozilla browser itself, deal with user information, new components,...