As the readme describes, 'CAT_BOX_HEADING_3' is an example of creating a heading for category id #3. There is no connection to category 46 except that category 3 (your "books") follows it. You now show the example headings for category 3, and an example image replacement for the category 3 name text.

To eliminate those, comment out the line you show, and delete the example image
/includes/templates/your_template/buttons/english/catimg3.gif.