Ask HN: Is there a name for the study and patterns of software extensibility?

I'm interested in the patterns and practices behind extending software. You know: extensions, plugins, add-ons, etc. -- the systems and features that software (usually enterprise software) provides so that users and extend it to do things it wasn't originally intended to do.

Is there a generally accepted name of category for this? I searched Amazon for some books on "software extensibilty" or "extending software," but didn't find anything outside of platform-specific books.

Ink and Switch has done a lot of research lately on what they called "malleable software," but that's a new term they invented, and doesn't have much traction.

I wrote this article for my work -- this is type of thing I've talking about: is there a name for the body of work/study around this type of thing?

https://staffbase.com/blog/integration-patterns