It’s not likely you’ll ever build web site versions targeting all languages and locations. Sometimes, you’ll need to present Google an indication of what do to any time a presented area or language isn’t obtainable or doesn’t exist. An x-default tag would be the URL that Google displays.  Mila is https://addons.prestashop.com/pl/seo-pozycjonowanie-naturalne/31857-automatyczne-google-rich-snippets-json-ld-opengraph-seo.html