How do Page Details > Search Engine Indexing options work?

I've recently become concerned about Google dinging our site for duplicate content, so I've been cleaning out duplicate content on an online development domain where I test Perch features.

I just now noticed the Page Details > Search Engine Indexing options. I don't remember these before upgrading to 2.6.

I've taken the trouble to check all three boxes on my dev domain, but I am curious how they work. I can't find documentation on them.

I would assume that to see a meta nofollow noindex tag in page source I would need to incorporate perch calls in the page template. Do I actually need to do this or, this being a dynamically served site, does the nofollow noindex message get passed some other way?