drupalcampbristol/core/modules/field_ui/field_ui.links.action.yml

field_ui.entity_view_mode_add:
  route_name: field_ui.entity_view_mode_add
  title: 'Add view mode'
  weight: 1
  appears_on:
    - entity.entity_view_mode.collection

field_ui.entity_form_mode_add:
  route_name: field_ui.entity_form_mode_add
  title: 'Add form mode'
  weight: 1
  appears_on:
    - entity.entity_form_mode.collection

field_ui.field_storage_config_add:
  class: \Drupal\Core\Menu\LocalActionDefault
  deriver: \Drupal\field_ui\Plugin\Derivative\FieldUiLocalAction