custom_form.field_list.item_states_form:
  path: '/admin/custom_forms/{custom_form}/fields/{item}/states'
  defaults:
    _form: '\Drupal\custom_forms_states\Form\CustomFormItemStatesForm'
    _title_callback: '\Drupal\custom_forms_states\Controller\TitleController::itemStatesTitle'
  requirements:
    _permission: 'edit custom form'
    custom_form: '\d+'
    item: '\d+'
  options:
    parameters:
      custom_form:
        type: 'entity:custom_form'
    _admin_route: TRUE