Yes I noticed this wire in both my cars...
It is not cut it actually goes into one of the fuse box connections, in the loom it is with.
Although I cant find out what it does, I thought it was probably something for the left hand drive cars?
I was concerned at first until I saw the exact wire in the other z. But it is not cut, if you turn it up to the connection block of that loom, if memory is correct, it fits into the top right? the only space in that block, and the length is correct.
But as said - I don't know its function.
:beer: