Buff Duration passives how it works/what affects ?

Hi guys i have a question im really confused about this passive node.

Buff Duration:

Increases Duration from Buffs and Debuffs you create from skills.

What does that mean ? Does it mean i can increase the duration for shock/freeze/burn i create from my skills ?

So does it increase the duration of stun i create from groundslam ?

plz help

So nobody know ?