Description of the extender pattern configuration.
The extender tracks extensions. The particularity of this architecture-style is that extensions are packaged in different bundles. An extension is detected by analyzing the bundle. The mark is currently a header in the bundle manifest. At each time a matching bundle appears or disappears, a callback is invoked.
Declaring the method to invoke when a matching bundle arrives
Declaring the method to invoke when a matching bundle leaves
Declaring the looked manifest header.