The only other example of this "hidden item quality" in the game I know of is <a href="/wiki/Cat_Upon_Your_Person" title="Cat Upon Your Person"><img alt="" src="/w/images/thumb/4/42/Placeholder2.png/20px-Placeholder2.png" decoding="async" width="20" height="26" srcset="/w/images/thumb/4/42/Placeholder2.png/30px-Placeholder2.png 1.5x, /w/images/thumb/4/42/Placeholder2.png/40px-Placeholder2.png 2x" /></a> <a href="/wiki/Cat_Upon_Your_Person" title="Cat Upon Your Person">Cat Upon Your Person</a>. That one's on the Wiki because the quality actually was visible on the item, and then patched to be invisible a few hours after release.

Part of the issue is that we can't actually observe the hidden quality, even by the usual methods that allow us to see <a href="/wiki/Fallen_London_Wiki:IDs_and_Hidden_Qualities" title="Fallen London Wiki:IDs and Hidden Qualities">IDs and Hidden Qualities</a>. The game engine lets you snoop on hidden qualities that are set as the result of an action, but not ones attached to an item, nor unlock conditions. So we know it must exist, but since we don't know its name or anything els about it, it's hard to document.