Values

Just the URL of the immoscout24 expose manager.

Code

...
$GLOBALS[ 'TCA' ][ $_table ][ 'ctrl' ][ 'immo24' ] = [
  'ctrl' => [
      'values' => [
          'urlexpose' => 'https://www.immobilienscout24.de/scoutmanager/exposemanager', // obligate
          'urlexposesandbox' => 'https://www.sandbox-immobilienscout24.de/scoutmanager/exposemanager',
      ],
...

Details

See details @ mapping.php in the samples Apartment, Contact and Site.