improvements-2.x-dev/modules/improvements_contact/tests/modules/improvements_contact_test/improvements_contact_test.routing.yml

improvements_contact_test.contact_form:
  path: /improvements-test/contact-form/{contact_form}
  defaults:
    _controller: \Drupal\improvements_contact_test\Controller\ImprovementsContactTestController::contactForm
    _title: Contact form
  requirements:
    _access: 'TRUE'