redirect-8.x-1.x-dev/modules/redirect_404/redirect_404.routing.yml

redirect_404.fix_404:
  path: '/admin/config/search/redirect/404'
  defaults:
    _title: 'Fix 404 pages'
    _form: '\Drupal\redirect_404\Form\RedirectFix404Form'
  requirements:
    _permission: 'administer redirects'

redirect_404.ignore_404:
  path: '/admin/config/search/redirect/404/ignore'
  defaults:
    _controller: '\Drupal\redirect_404\Controller\Fix404IgnoreController::ignorePath'
  requirements:
    _permission: 'administer redirect settings+ignore 404 requests'
    _csrf_token: 'TRUE'