What is the Difference in bones_comments() and comments.php

Question

I started to use Bones HTML5 Wordpress Starter Theme, but a little confuse with some built-in function in bones,

There is function bones_comments() in functions.php but I cannot find anywhere on the files where this function is used or called.

And I take a look at the code in the function it just looks like some code to output wordpress comments, and yet there is comments.php for comment_template() in wordpress.

So really confuse why bones add the bones_comments() function and not use it. and what is the difference between bones_comments() and comments.php

Answer 1

It is a function created to be used as a hook.

Inside the comments.php file is

<?php wp_list_comments('type=comment&callback=bones_comments'); ?>

So you can add whatever you want to the bones_comments() function and have it added to the comment output.