Gregor and the Marks of Secret: 4

The individual or group credited with creating the main content of a product, such as a book, film, or other creative work. The value is a free‑text string representing the name(s) of the primary creator.

Indicates the physical or digital format in which a product is presented, such as "Hardback", "Paperback", "DVD", "Blu‑ray", "Vinyl", or other media types. The value may contain multiple comma‑separated items to represent combined attributes (e.g., "Hardback, Illustrated").

The age range for which a product is intended or recommended, expressed as a minimum and maximum age in years.

The total count of individual pages contained in a book or printed publication. It represents the number of physical sheets that make up the product, regardless of layout or formatting.

The calendar date on which the product was first made available to the public or released for sale. It is expressed as a full year, month, and day (YYYY-MM-DD) and can be used to filter or sort items by release period.

The name of the entity that publishes or distributes the product, such as a book, magazine, or other media item.

The mass of the product expressed in a standard unit such as grams or kilograms. It represents how heavy the item is and can be used for shipping calculations, handling instructions, or consumer information.