From publisher blurb:
Though several thieves fancy themselves to be in legitimate pursuits of treasure, the truest Treasure Hunters are devoted to the recovery of legendary Artifacts. A Treasure Hunter’s reasoning for this quest will vary from person to person, but all approach their legendary quarry with the utmost fervor and commitment.
Building off of the existing Fifth Edition rules to build a ranger character, rangers of the Treasure Hunter archetype are questants in search of the most powerful of magical items - Artifacts. In pursuit of these artifacts, they'll learn new ways to use magical items truly become the stuff of legends. Furthermore, this PDF contains a sidebar with some typical narrative constructs for Game Masters to consider in quests revolving around artifacts.