Introduction
Godot Kotlin/JVM libraries are basically the equivalent of Godot Addons, but specifically for the use in other Godot Kotlin/JVM projects like Games or Applications.
Relevance
If you build a library which does not register any classes to Godot, you can just create a regular JVM library, and you will have no need for this documentation.
Overview
A Godot Kotlin/JVM library is just a regular JVM library with additional metadata annotations for registered classes. For registered classes in a library registration files are generated and provided to the consumer, so they can be used in the consuming project.