I’m really confused how the author generated 88 documents in Preview that are unsaved. What kind of documents and changes were these? Why were they not saved w

I’m really confused how the author generated 88 documents in Preview that are unsaved. What kind of documents and changes were these? Why were they not saved when the changes were made? Preview is mainly used to view image files and do simple editing. Those edits are auto saved as you go long. I’m sure the author has a point but I’m just distracted by this strange use case.