Arrgh: I think I know where you're at.
You have the book in a calibre library and you're looking at the content of the book folder:
You should regard calibre libraries as black boxes. The folder and file names in calibre library folders are determined by a calibre algorithm. Here's a couple of links that explain the rationale:
Want to change folder structure or file names in the Calibre library?
Why doesn’t calibre let me store books in my own folder structure?
BR