These tea leaves appear to be the hardest-to-obtain ingredient in the new Karakul and Marid leather recipes, so I figured I'd try my hand at harvesting them in Bhaflau Thickets. Ended up with about 4 stacks of them in just under 3 hours.
Also used for a new Black ink recipe in alchy would be a viable alternative to nebomites if you harvest your own leaves, the fish are dirt cheap and catchable from the dock in aht urgan with a sabaki rig
These are used to make Marid Leather and Karakul Leather and are obtained by Harvesting in the Woodlands and Thickets. I have not seen a vendor that sells these yet, but you cannot substitute these for the Windurst Tea Leaves.