Where does hidden "You are here" h2 heading in breadcrumb come from?

Hi,

this is the output I get in my custom theme based on Omega:

<div id="breadcrumb" class="grid-25"><h2 class="element-invisible">You are here</h2><div class="breadcrumb"><a href="/">Home</a></div></div>

Due to SEO reasons, I want to avoid any hidden text, especially in h2 heading. I have tried to find where does this output come from, but unsuccessfully. There are no signs of it in any of tpl.php, .inc or similar files.

Could someone please explain me how to get rid of it?