Jetpack SDK 4.0 With Four High-Level APIs
Mozilla have announced the release of Jetpack SDK version 0.4.
This version adds four high-level APIs. These include the page-worker API that grants add-ons the ability to create permanent, invisible frames for loading and accessing web pages, and a simple-storage API for allowing add-ons to store data across application restarts.
In addition, add-on bundles created by the Jetpack SDK can be installed into nightly testing builds of Firefox, without requiring the application to restart.