listjs-8.x-1.x-dev/tests/modules/listjs_theme_test/listjs_theme_test.routing.yml

listjs_theme_test.default_controller_render:
  path: '/listjs-theme-test'
  defaults:
    _controller: '\Drupal\listjs_theme_test\Controller\DefaultController::render'
    _title: 'List.js theme test'
  requirements:
    _permission: 'access content'