message_digest-8.x-1.x-dev/config/schema/message_digest.schema.yml

message_digest.interval.*:
  type: config_entity
  label: 'Message digest interval'
  mapping:
    id:
      type: string
      label: 'ID'
    label:
      type: label
      label: 'Label'
    description:
      type: text
      label: 'Description'
    interval:
      type: string
      label: 'Digest interval'