saml_sp-8.x-3.x-dev/modules/saml_sp_drupal_login/saml_sp_drupal_login.routing.yml

saml_sp_drupal_login.config:
  path: /admin/config/people/saml_sp/login
  defaults:
    _title: 'SAML'
    _form: \Drupal\saml_sp_drupal_login\Form\SamlSpDrupalLoginConfig
  requirements:
    _permission: 'configure saml sp'

saml_sp_drupal_login.login:
  path: /saml/drupal_login/{idp}
  defaults:
    _title: 'Initiate SAML SP Drupal Login'
    _controller: \Drupal\saml_sp_drupal_login\Controller\SamlSPDrupalLoginController::initiate
  requirements:
    _access: 'TRUE'
  options:
    _maintenance_access: TRUE

saml_sp_drupal_login.register:
  path: '/user/saml_sp_drupal_login_register'
  defaults:
    _entity_form: 'user.register'
    _title: 'Request an account'
  requirements:
    _custom_access: '\Drupal\saml_sp_drupal_login\Controller\SamlSPDrupalLoginController::access'