Hello Zeno_McDohl,

Nice catch!

During the stream, Yoshida showed off an image (the one you pointed out) of a new dungeon-like content which is currently planned for release in Patch 3.3. It's being referred to internally as the Treasure Hunter dungeon.

Uncovering treasure maps, such as a timeworn dragonskin map, may sometimes reveal an entrance to the dungeon instead of the usual treasure chest. Once revealed, players have the option to challenge it or not, and by entering, players would need to clear out the monsters within this dungeon in order to unlock chests. The difficulty isn't set too high and they can be cleared without any practice. The image shown was just an example of the final room players can reach, which is filled with treasures. Players would need to do something to levers located in the rooms; however, the full details will be shrouded in mystery for now!