core/homeassistant/components/logbook/services.yaml

log:
  description: Create a custom entry in your logbook.
  fields:
    name:
      description: Custom name for an entity, can be referenced with entity_id
      example: "Kitchen"
    message:
      description: Message of the custom logbook entry
      example: "is being used"
    entity_id:
      description: Entity to reference in custom logbook entry [Optional]
      example: "light.kitchen"
    domain:
      description: Icon of domain to display in custom logbook entry [Optional]
      example: "light"