Dagger 2: What does @Module(includes =) do?
See the docs for Module.includes:
Additional
@Module-annotated classes from which this module is composed. The de-duplicated contributions of the modules in includes, and of their inclusions recursively, are all contributed to the object graph.
In short, yes, Module.includes is a way of adding a dependency on the listed modules (AddonModule, VersionModule, and AboutModule in your example) from anything that includes the enclosing Module (CoreModule in your example).