Board Thread:Questions and Answers/@comment-88.110.77.129-20141204223028/@comment-6697950-20141204224522

There is a single reference to it in the series:

"Although the labyrinth we went to had already been cleared, there were still unexplored areas within it. One of the members discovered a treasure chest when we were preparing to leave. I recommended leaving it alone, as we were close to the front lines so the monsters had high levels. Furthermore, I didn't trust the trap dismantling skills of the members. But since only Sachi and I opposed opening the treasure chest, we lost 3 to 2 on the vote."

So yes, it does exist, just that nobody noticed that it wasn't listed.

Edit: Lol, TUSF cut in front of me, but my reply is a suitable follow up to his post XD

Anyway, skill added to the list with a reference.