The book doesn't have highlighting OR notes. What it does have is a sidecar file which the applications read in order to generate your notes/highlights.
If you highlight from a Kindle e-ink device, I know a file called "My Clippings.txt" is created, which can be imported into calibre using the
Annotations plugin, into a configured custom column. When inserting a metadata jacket into a book (using calibre's Polish Book option) this column should be included.