drupal_libcal-1.x-dev/libcal.routing.yml

libcal.libcal_api_config_form:
  path: '/admin/config/libcal'
  defaults:
    _form: '\Drupal\libcal\Form\LibcalAPIConfigForm'
    _title: 'LibCal Integration'
  requirements:
    _permission: 'administer site configuration'
  options:
    _admin_route: TRUE