Quicklinks are used for creating custom links in the center af Your Admins startpage.
Links can point to any internal as well as external page.

The quicklinks.php file is located in includes/modules/themes/fuctions/

quicklinks.php . Customers can add/edit links in the file as per the needs.

It is calling from admin’s index.php

The main  target of quicklinks is customers/resellers  can make their own links on their site. It shown on the admin’s index page under the section ‘Shortcuts’.  Quicklinks can be used for calling resellers own custom applications in the admin .

If /includes/modules/themes/functions/quicklinks.php is present, then that's the one used in admin=> index.php  . Otherwise it will use defaults version on the admin(shop_admin/includes/modules/quicklinks.php)

Following is an example of adding a quicklink  for categories/products

<tr class="infoBoxContent"><td height='25'><a href='<?php echo bg_href_link(FILENAME_CATEGORIES , '', 'NONSSL');?>'><?php echo bg_image(DIR_WS_IMAGES . 'icons/products.png') . ' ' . BOX_CATALOG_CATEGORIES_PRODUCTS;?></a></td></tr>