Edit leave a reply

Hi, I would like to edit part of the leave a reply field. I want to add the text “(optional)” next to where it says email when filling out the form as we removed that requirement. I think I am suppose to look in my theme comments.php, but all I see is function calls, which are defined in some other file I am unable to locate.

<!-- Begin @response response_before_comments hook content-->
	<?php response_before_comments(); ?>
<!-- Begin @response response_before_comments hook content-->

<!-- Begin @response response_comments hook content-->
	<?php response_comments(); ?>
<!-- Begin @response response_comments hook content-->

<!-- Begin @response response_after_comments hook content-->
	<?php response_after_comments(); ?>
<!-- Begin @response response_after_comments hook content-->

So does anyone know how to edit this text in the eclipse theme? Does anyone know what the correct file is that I should have opened? Thanks.