I don't know what it is, but Dan Slott really likes to rub it in that he took Jessica off the board.
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Peter asks Julia if Jessica can be restored, and Julia is hesitant to say 'yes' at first, until the golden idol of Neith is brought up as a means of weaving new threads....they retrieve it, only for the idol to be destroyed by a headbutt...and then Anya says "that was her last hope, there is no way of restoring Jessica"
Of course, the big ray of hope here is that
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Peter is then stabbed with the dagger and 'wiped' from existence, so if we see him again in this story, we'll presumably see Jessica