An `ExtensionPoint` is implemented by classes marked `@Extension`, which are singletons contributed by plugins, sometimes known as a service registry pattern. This is the fundamental mechanism by which Jenkins plugins add functionality. An admin does not configure the _set_ of extensions, though a particular extension may have configurable properties (typically as a `GlobalConfguration`). Extensions need not have any presence in the UI whatsoever. They are found via `ExtensionList`.
A `Descriptor` is a special kind of extension which registers an implementation class of associated `Describable`, sometimes also serving as a factory. `Describable` instances are defined by an admin or other user via the GUI or configuration-as-code, use `@DataBoundConstructor` & `@DataBoundSetter`, are intended to be persisted using XStream, and are typically values of a property or elements of a list defined in turn by something else—a job property, a build step, a piece of global configuration, some other `Describable`, etc. I am not sure exactly which documentation you are referring to but perhaps it needs to be patched. -- You received this message because you are subscribed to the Google Groups "Jenkins Developers" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/jenkinsci-dev/CANfRfr2G1QZtrhWT6LMg%2B_ipnP7UXvnumLLSY5psAS%2B%3DjyTfTw%40mail.gmail.com.
