widget_engine-8.x-1.2/widget_engine.routing.yml

widget_engine.widget_preview:
  path: '/widget-engine/{widget_id}/preview'
  defaults:
    _controller: '\Drupal\widget_engine\Controller\WidgetPreviewController::widgetPreview'
  requirements:
    _permission: 'access content'
    widget_id: \d+

widget_engine.widget_preview_save:
  path: '/widget-engine/{widget_id}/save-preview'
  defaults:
    _controller: '\Drupal\widget_engine\Controller\WidgetPreviewController::widgetPreviewSave'
  requirements:
    _permission: 'access content'
    widget_id: \d+

widget_engine.widget_preview_generate:
  path: '/admin/content/widget/{widget}/generate-preview'
  defaults:
    _controller: '\Drupal\widget_engine\Controller\WidgetPreviewController::widgetPreviewGenerate'
  requirements:
    _permission: 'add widget entities+edit widget entities'
    widget: \d+
  options:
      _admin_route: TRUE