What does it mean for literature to be “reflective”?

Question

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.

Answer 1

I asked @thestorygraph on Twittter:

What exactly are the criteria for the tag/mood "reflective" on @thestorygraph?
Or should I ask @nodunayo and @RobFrelow ?

(Nadia Odunayo and Rob Frelow are co-founders of The Storygraph.)

This was the answer:

There is no set criteria for it! Typically a book that is thought-provoking, deliberative, references past memories, etc., would have that tag!

"Reflective mood" is otherwise not known to me as a specific literary term. For example, it is not defined in The Concise Oxford Dictionary of Literary Terms by Chris Baldick (Oxford University Press, 2001). That doesn't mean Baldick doesn't use the term, but two of the three occurrences of the term are related to Horace; for example:

The Horatian ode, as distinct from the Pindaric ode, is homostrophic and usually private and reflective in mood: Keats's odes (1820) are English examples of this form.