The book-review and -recommendation site The Storygraph allows users to categorise books in various ways such as adventurous, funny, inspiring, and reflective. Some (fiction) books I know have been judged to be reflective by many reviewers while others not at all, so there seems to be some agreement on the meaning of this. However, I fail to see what distinguishes these books, and thus I ask: When is literature categorised as reflective?
I can think at least of the following interpretations, at least some of which are clearly distinct:
The author discusses the events of the story on page, i.e., the book is the product of reflective writing.
The characters (or the third-person narrator) discuss the events of the story.
The story holds up the mirror to the reader.
The author explores real-world questions or events by means of telling a story.
Any reasonable Internet search I could come up with yielded primarily information on reflective writing or reflections on literature.