Drifter's Cache

There are four piles of rubble(3 actually, one is called a "Runestone") scattered throughout the zone; one at the southwest exit, one southwest of the bridge, one in the center part of the zone and one in the Deepstalker Cave(You'll know you're at the right place when you get attacked by a Deepstalker Matriarch) at the East side of the zone (towards the south).

Interacting with these piles will give you codex updates and after obtaining all 4 codex updates, there will be a "quest" marker pointing out the location of the Drifter's Cache. It contains the Effort gloves as well as a dagger (Thorn of the Dead Gods), a ring (Ring of the warrior - +2dex / str) and a few other items.