Treasure Hunter Quest NPC can be found at Britain Bank. Upon completing enough treasure maps, you will be able to chose between rewards:

LEVEL 6 TREASURE MAP: More rewarding treasure map, will also have a chance of spawning a Mini Boss.
RANDOM DECORATION: Obtain a rare decoration.
HUED ITEM: Obtain an hued item with an hue exclusive to this system (Greed). Obtained item is random, could be a spellbook dye, furniture dye, cloth, backpack dye, hair dye etc..

In order to obtain "Map knowledge" points, you will need to destroy your chests after looting it. To do so, simply click it once and use the destroy chest option.