What is Stunbreak Stability in Berserk mean?

There are two stun durations in Warrior's Berserk mode: Berserk Stability at 8s and Stunbreak Stability at 3s. I could not find the term stunbreak stability on the wiki. I don't play a warrior and am asking this for a friend who does not speak english very well. Can someone explain the difference, or what conditions they show up under?.

you can find this in berserker build

Eternal champion:

when you get into "berserk mode" you will get 3 stack of Stability for 8 sec.

and when you break stun you will get 1 stack of Stability and also 3 stack of might. ( whatever you are in berserk mode or not )

Thank you for the reply. I'll relay it. The 8s we understood, and your explanation of the stun break corrects our guess of what it does. We guessed incorrectly it only counted if the stun break happened during the 15s active Berserk mode.