This should be labeled as a demo. It's reusing an existing map from the main Thief campaign so most of the architecture and actual building was done by the devs of the game. What is great is how it showcases in game conversations, passing of items from NPC to PC, new audio for NPCs and PC, a safe to crack finding an actual code, etc.

Very nicely done, but too short and too much missing for it to be called a legit mission.

Two of the objectives also didn't work for me, but that could be a Newdark issue. Still, it's odd that I found the gem and that objective was ticked off, but the one to get inside where the gem resided was not.