See at a glance if your 12 Atonements are going to last long enough for the upcoming raid burst damage, or if you will need to get another radiance out first.
Atonement Bar is a simple progress bar which counts down how many seconds you have left with a certain number of Atonement buffs out on the group. The bar is broken down into up to 3 colored sections for different numbers of Atonement buffs.
This addon is intended to give you an overview to help with planning your next few moves, and is best paired with unit frames which can indicate exactly which users have Atonement, such as Grid or ElvUI.
Options can be found in the AddOns section of the Interface options menu.