A: 5 - ui/main/MainActivitySubcomponent.java

MainActivitySubcomponent.java

// TODO (ContributesAndroidInjector) remove this in favor of @ContributesAndroidInjector
@PerActivity
@Subcomponent(modules = MainActivityModule.class)
public interface MainActivitySubcomponent extends AndroidInjector<MainActivity> {

    @Subcomponent.Builder
    abstract class Builder extends AndroidInjector.Builder<MainActivity> {
    }
}