redirect-8.x-1.x-dev/modules/redirect_domain/redirect_domain.routing.yml

redirect_domain.domain_list:
  path: '/admin/config/search/redirect/domain'
  defaults:
    _title: 'Domain redirects'
    _form: '\Drupal\redirect_domain\Form\RedirectDomainForm'
  requirements:
    _permission: 'administer redirects'