micro_menu-8.x-1.0-alpha4/micro_menu.links.action.yml

site.menu.add_link_form:
  route_name: site.menu.add_link_form
  title: 'Add link'
  class: \Drupal\menu_ui\Plugin\Menu\LocalAction\MenuLinkAdd
  appears_on:
    - entity.site.edit_menu