content_entity_builder-8.x-1.x-dev/content_entity_builder.links.action.yml

content_entity_builder_type_add:
  route_name: content_entity_builder.type_add
  title: 'Add content entity type'
  appears_on:
    - entity.content_type.collection
content_entity_builder.content_add:
  class: \Drupal\Core\Menu\LocalActionDefault
  deriver: \Drupal\content_entity_builder\Plugin\Derivative\ContentEntityBuilderLocalAction