This documentation describes which properties are required, recommended, or optional for structured facts with special meaning to Google Lookup. Most Research structured knowledge employs schema.org vocabulary, but you'll want to count on the Google Research Central documentation as definitive for Google Search habits, as opposed to the schema. Google does https://addons.prestashop.com/de/seo-suchmaschinenranking-optimization/31857-automatische-google-rich-snippets-json-ld-opengraph-seo.html