external_data_source-8.x-2.2/external_data_source.routing.yml

external_data_source.auto_complete_controller:
  path: '/external_data_source/autocomplete'
  defaults:
    _controller: '\Drupal\external_data_source\Controller\ExternalDataSourceController::autocomplete'
    _title: 'External Data Source Autocomplete'
    _format: json
  options:
    no_cache: TRUE
  requirements:
    _permission: 'access content'