Not yet observed in the beta: the Forever client retains this item's record without its stats. Those are sent by the server in-game.Until someone records it, the Classic tooltip is shown below. Forever has reviewed every dungeon's loot, so changes are expected.
In Classic Era, dropped by Guzzler, Blackrock Depths(14%).
Classic 1.15.9.69722
Wayfarer's Knapsack
Binds when picked up
Unique
Bag
16 Slot Bag
Sell Price: 87s 50c
Forever Beta 1.60.1.70009
This item does not exist in the Forever client.