Certification information about a product, organization, service, place, or person.

The [GS1 digital link](https://www.gs1.org/standards/gs1-digital-link) associated with the object. This URL should conform to the particular requirements of digital links. The link should only contain the Application Identifiers (AIs) that are relevant for the entity being annotated, for instance a [Product](https://schema.org/Product) or an [Organization](https://schema.org/Organization), and for the correct granularity. In particular, for products: - A Digital Link that contains a serial number (AI `21`) should only be present on instances of [IndividualProduct](https://schema.org/IndividualProduct) - A Digital Link that contains a lot number (AI `10`) should be annotated as [SomeProducts](https://schema.org/SomeProducts) if only products from that lot are sold, or [IndividualProduct](https://schema.org/IndividualProduct) if there is only a specific product. - A Digital Link that contains a global model number (AI `8013`) should be attached to a [Product](https://schema.org/Product) or a [ProductModel](https://schema.org/ProductModel). Other item types should be adapted similarly.

Keywords or tags used to describe some item. Multiple textual entries in a keywords list are typically delimited by commas, or by repeating the property.

A person or organization who owns this Thing.

The telephone number.

A page providing information on how to book a tour of some [Place](https://schema.org/Place), such as an [Accommodation](https://schema.org/Accommodation) or [ApartmentComplex](https://schema.org/ApartmentComplex) in a real estate setting, as well as other kinds of tours as appropriate.

URL of the item.