Shows a timer for Xira the Underhanded's Opportunity Strikes stun. The first stun happens at around 15-17s after encounter start, and the following stuns always exactly 30s after the last one, regardless of whether Xira was interrupted or not.
At 5s before the stun (green tick), the bar turns green and an Air Horn sound plays so that players can prepare to stun Xira.
Because the first stun time can vary a bit, the first timer in the fight might be 1-2s too early.