Change Field Label from h2 to div

Hi, I am looking for days the PHP file which characterizes the Field label with the <h2> tag.
From a certain number of <h2> tags that SEO is technically quite counterproductive.

Can Someone show me how or where to
<h2 class = "field-label"> Taxonomy Term: </ h2>
in
<div class = "field-label"> Taxonomy Term: </ div>
can change?

I found this solution, among other things, but nothing works.
http://drupal.stackexchange.com/questions/83263/change-a-label-element-t...

Thank you very much