The set is named "Kul Tiras Quest", which is the naming usually given to leveling items, with the name of the zone in which you get them. So that naming scheme translates to "Items obtained in Kul Tiras". Which can only be interpreted by "We will get a Kul Tiras zone in the next expansion".
We only have an item set, that may have been included by mistake. What did you expect, to see "New race: Naga" etched in the texture?