How do I set document_base_url?

Cockpit v2
1

I’ve tried in my config.php:

<?php
return [    
      'editor' => [
        'tinymce' => [
            'relative_urls' => false,
            'remove_script_host' => false,
            'document_base_url' => 'https://www.cms.mycontentmanager.com',
        ],
    ],

];