@Chessty_McBiggins I am of-course a pazter who can't play chess. and if "inhuman" is not the proper word to describe the situation, I apologize - I am not a native English speaker and my English is rusty, so please pardon my language. (FYI, I just want to convey that this is not possible for anyone to find the move - not in the sense of attacking anyone, claiming them morally oblige to find a chess move)
Here's my take: I think it's very safe to say that nobody found the move during the game, and I really doubt if anyone would find the move on their own. From what I've read, Svidler received the move during his broadcast (with sasha, because people are spamming "mate in 30" in the chatbox), but he was unable to figure out why it was winning (at that time, at least); Ian Rogers also ask about the move during the press conference, but Carlsen and Caruana seems to be puzzled and confused. And if they can't find it, I think it's pretty safe to say that this is a move nearly impossible to be found by human - let alone find with a time limit and in a regular game!
It might have been found if it was a puzzle, or in a post mortem, or in correspondence Chess. But not really in a regular game, let alone in the context of a WCC and with time trouble. But I could be wrong, and I hope I am wrong, though I highly doubt it.