ComponentActivity.java

@NonNull
@Override
public ViewModelProvider.Factory getDefaultViewModelProviderFactory() {
   ...
   mDefaultFactory = new SavedStateViewModelFactory(
      getApplication(),
      this,
      getIntent() != null ? getIntent().getExtras() : null); // ◀ Activityに渡されたArgumentを代入
   ...
   return mDefaultFactory;
}