Isn't this missing default configuration / schema?

Problem/Motivation

I just looked into the EntitySubmenuBlock class and thought: Isn't this missing default configuration / schema?

The block introduces settings, but doesn't make use of defaultConfiguration()?
https://www.drupal.org/docs/creating-modules/creating-custom-blocks/add-...

  /**
   * {@inheritdoc}
   */  
  public function defaultConfiguration() {
    return [
      'lorem' => $this->t('ipsum'),
    ];
  }

For the settings introduced, see blockForm()

Guess schema isn't needed then?

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes