Drupal → Добавить сторонней контент сущности своё базовое поле (base field)

// MODULENAME.module
 
/**
 * Implements hook_entity_base_field_info().
 */
function MODULENAME_entity_base_field_info(EntityTypeInterface $entity_type) {
  if ($entity_type->id() == 'taxonomy_term') {
    $fields = [];
 
    $fields['stored_depth'] = BaseFieldDefinition::create('integer')
      ->setLabel(t('Depth'))
      ->setSetting('unsigned', TRUE)
      ->setDefaultValue(0);
 
    return $fields;
  }
}

// MODULENAME.install
 
/**
 * Add term depth base field.
 */
function MODULENAME_update_8001() {
  $depth_field = BaseFieldDefinition::create('integer')
    ->setLabel(t('Depth'))
    ->setSetting('unsigned', TRUE)
    ->setDefaultValue(0);
 
  \Drupal::entityDefinitionUpdateManager()->installFieldStorageDefinition('stored_depth', 'taxonomy_term', 'MODULENAME', $depth_field);
}