Edit Default Blogroll

Trying to edit the default blog roll. Found a few references to it but could not find the file in question:

"If you want to set your own links in the blogroll, you can do that by modifying lines 1478 to 1481 at /wp-includes/wpmu-functions.php

If you do, although you should never modify the source code directly, I strongly recommend you to reuse what you have without adding a single line of code. That is, add as much as two new links by reusing the two existing ones at lines 1478 and 1479."

Can somone direct me to the proper file please.