redirect-8.x-1.x-dev/modules/redirect_domain/config/schema/redirect_domain.schema.yml

redirect_domain.domains:
  type: config_object
  label: 'Redirect domains'
  mapping:
    domain_redirects:
      type: sequence
      label: 'Domain redirects'
      sequence:
        type: sequence
        sequence:
          type: mapping
          mapping:
            sub_path:
              type: string
              label: 'Sub path'
            destination:
              type: string
              label: 'Destination'