URL <strong>including protocol</strong> to use for this language, if your <em>Detection and selection</em> settings use URL domains. For the default language, this value may be left blank. <strong>Modifying this value may break existing URLs. Use with caution in a production environment.</strong> Example: Specifying "http://example.de" or "http://de.example.com" as language domains for German results in URLs like "http://example.de/contact" and "http://de.example.com/contact", respectively.