tamper-8.x-1.x-dev/tests/modules/tamper_test/tamper_test.routing.yml

tamper_test.form:
  path: '/tamper_test/{entity_test_bundle}/{tamper_plugin_id}'
  defaults:
    _form: '\Drupal\tamper_test\Form\TamperForm'
    _title: 'Tamper test form'
  options:
    parameters:
      entity_test_bundle:
        type: 'entity:entity_test_bundle'
  requirements:
    _access: 'TRUE'