betasite-1.0.4/modules/betasite_switches/betasite_switches.routing.yml

betasite.admin_config_development_betasite:
  path: '/admin/config/development/betasite'
  defaults:
    _controller: '\Drupal\system\Controller\SystemController::systemAdminMenuBlockPage'
    _title: 'Beta Site'
  requirements:
    _permission: 'access administration pages'