drupal/core/modules/datetime/config/schema/datetime.schema.yml

# Schema for the configuration files of the Datetime module.

field.datetime.settings:
  type: mapping
  label: 'Datetime settings'
  mapping:
    datetime_type:
      type: string
      label: 'Date type'

field.datetime.instance_settings:
  type: sequence
  label: 'Settings'
  sequence:
    - type: string

field.datetime.value:
  type: sequence
  label: 'Default value'
  sequence:
    - type: sequence
      label: 'Default value'
      sequence:
        - type: string
          label: 'Value'