Ever since i started playing again like a month ago and had enough CP to spec into Treasure Hunter I've been asking people in game exactly what it does.
Unfortunetly I continually get conflicting answers to the point i think i've heard a dozen different explanations.
-Have the Devs ever commneted about it?
some of the theories I've herad:
1. It effects ALL loot drops, chests, bosses, etc.
2. It increases the quality of all chest drops including locked chests and dark anchors, and it is the only way to get gold drops from both chests.
3. It only effects locked chests, improving the quality of drops.
4. It only effects locked chests, and works basically upgrading the items found to what would be in one higher level chest lock.