This item dropped for me today while killing the mobs in the room near where Tawro Icequake spawns. The door to click in SWT, however, no longer exists. As far as I can tell it has replaced with a mob related to mage epic 1.5/2.0
There was originally supposed to be a zone between Umbral Plains and Shadeweaver's Thicket.
There's a BUNCH of lore here if you want it: ( http://eqforums.station.sony.com/eq/board/message?board.id=Lore&message.id=6171 )
The keyed door in Shadeweaver's is presumably the one that leads to Umbral Plains (http://www.eqatlas.com/luclin/shadeweaversthicketmap.html -- listed on top of the map as "to unknown zone")
The zone was, according to the lore in Luclin, meant to be called "Firefall Keep", as it was used in the Vah Shir battle against the Akhevans led by Vah Kerrath, Taruun, Jharin, Khala Dun, and Dar Khura (Khati Sha was not present, having already left Shar Vahl and ended up being tortured in Ssraeshza before going mad and becoming Khati Sha the Twisted)
The zone was never put in as far as I can tell. Probably a symptom of the fact that 6 months into luclin development, large portions of the development and direction teams left sony and followed Brad.
As soon as I get one of these things, I'll be corpsing it and just making a quick trip to shadowrest any time I think I'll need it.
We got this key the other night from Radir Fireshadow's bosses in the tunnels near where Rumblecrush spawns. The key was no rent, but allowed me to click the tunnel end and port to shadeweaver's thicket. (= Kind of a unique little escape item.