I've also been too lazy to experiment in my test wiki. I've been stymied by the purpose of the four slashes in the "A-Z\\^" part of that string. It might be obvious to some but not to me. Is there a need to double many of the \s here?
I would imagine the doubling of 's is for escaping purposes, although why you'd end up with 4 in a row, I've no idea. I never did get the hang of regular expressions.