geolocation-8.x-3.x-dev/modules/geolocation_geometry/geolocation_geometry.routing.yml

geolocation_geometry.geometry_format_file_download:
  path: '/geolocation/geometry-file-download/{format}/{entity_type}/{entity_id}/{field_name}/{delta}'
  defaults:
    _controller: '\Drupal\geolocation_geometry\Controller\GeometryFormatFileDownloadController::download'
    _title: 'Geometry File Download'
    format: 'geojson'
    delta: -1
  requirements:
    _permission: 'access content'
  options:
    parameters:
      format:
        type: string
      entity_type:
        type: 'entity:type'
        constraints:
          type: '[a-zA-Z_]+'
      entity_id:
        type: 'entity:id'
      field_name:
        type: 'string'
      delta:
        type: 'integer'