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

entity.alert.add_form:
  route_name: entity.alert.add_page
  title: 'Add Alert'
  appears_on:
    - entity.alert.collection

entity.alert_type.add_form:
  route_name: entity.alert_type.add_form
  title: 'Add Alert type'
  appears_on:
    - entity.alert_type.collection