form_mode_manager-8.x-1.x-dev/modules/form_mode_theme_switcher/form_mode_manager_theme_switcher.routing.yml

# Settings route.
form_mode_manager.theme_switcher_settings:
  path: '/admin/config/content/form_mode_manager/theme-switcher'
  defaults:
    _form: 'Drupal\form_mode_manager_theme_switcher\Form\FormModeThemeSwitcherForm'
    _title: 'Form Mode Manager theme switcher settings'
  requirements:
    _permission: 'administer site configuration'
  options:
    _admin_route: TRUE