What is considered "additional content"?

[Camilla]

The Librarian Manual states that calendars are not considered books, "unless containing additional content". What is meant by "additional content"? Do photos fall in the additional content category, or does the additional content always have to be text?
E.g. calendars here https://www.goodreads.com/author/list...

[rivka, Former Moderator]

Those would not qualify. The additional content would generally be text.

[Camilla]

Thank you for the reply, I thought so but wanted to confirm.