underscores theme – any way to exclude categories from single post navigation?

Hi there – I’m building off of _s (underscores) starter theme, and searching for a way to exclude certain categories from the <?php underscores_content_nav( 'nav-above' ); ?> function – but I can’t find where this lives in the templates (it’s not in functions.php).

I’ve excluded the categories in question from the main index loop, but once you’re navigating between single posts, all posts show up.

For instance, I want to exclude the Giveaways category (ID 1697) from this post’s pagination:

http://www.consciousdivas.com/dev/kimberlyriggins/14-ways-to-up-your-confidence

Any suggestions would be appreciated!
Thanks!