This is not correct. That's not an Extension Point. That's a plugin interface. Extension Points are a type of plug-in, but have the specific feature of not running in the host application's address space meaning that many types of bugs and security attacks are not possible. For example, if an Extension Point dereferences NULL, it will crash, but the host app can restart it and reconnect without losing any data. If a Photoshop plug-in dereferences NULL, Photoshop crashes.

Ah, yeah, that's an interesting distinction I hadn't thought of. Any idea what the first example of that type of extension was? My gut says that'd still been done long before android

IPC has been a systems feature for a while, but discovery is a higher level thing needed for this sort of plugin interface. COM and CORBA are ancestors I know about.