This is simply a edited and modified version of "Healium" Add-on, For those who don't know this is a heal addon much like HealBot addon in many ways.
This one has been edited and modified so that it will display the agro threat of anyone within the healium UI. The users HP bar will turn to a dark blue and indicate via text they have threat within healium. This makes it a little more useful for allowing you to know who is getting attacked or is about to get damage from agro threat.
Updated some of the script to fix a few of the bugs healium UI had by default, One of the major bugs fixed is your own characters UI not showing in healium with rest of party. So with this update it will insure all group/party/raid members will be displayed in healium UI when entering new instances and maps.