What I mean is the headings above each category that might appear on a blog's home page. For example, a news website's homepage might have a category headings like "Politics" "Sports" and "Business" set to H3, then under that it will have the article titles set as H2.
I have seem some themes even set the category heading to H4-H6.
What's optimal for SEO? In my mind, the category headings would be H2, then the article titles would be H3.
But of course, I know very little about SEO at this point.