Security fix. See SA-CONTRIB-2012-083 - Taxonomy List - Cross Site Scripting (XSS).
Fixes SA-CONTRIB-2012-081 - Aberdeen - Cross Site Scripting
If you copied code from the aberdeen_breadcrumb function into a custom sub-theme's template.php file you should compare your code to the changes to ensure that menu_get_active_title() is properly wrapped in check plain like:
menu_get_active_title()
check_plain(menu_get_active_title());
See SA-CONTRIB-2012-080 - Hostmaster (Aegir) - Access Bypass and Cross Site Scripting (XSS) for details.
Changes since 6.x-1.8:
Changes since 6.x-1.0:
See SA-CONTRIB-2012-77 - Advertisement - Cross Site Scripting & Information Disclosure.