examples-3.x-dev/modules/pager_example/pager_example.routing.yml

pager_example.page:
  path: '/examples/pager-example'
  defaults:
    _title: 'Pager Example'
    _controller: '\Drupal\pager_example\Controller\PagerExamplePage::getContent'
  requirements:
    _permission: 'access content'