The only reason this got through my original review was because PEP 540 was implemented when I was going through a personal situation that lead to me quitting my job cold without a new one to go to, so my review of Victors changes to the PEP 538 implementation was pretty cursory.

Now that I've finally reviewed it properly, I can see those changes were fundamentally misguided, and completely missed the intent and purpose of the PEP - it's deliberately designed to work completely differently from PEP 540, but Victor's now turned it into a pale shadow of the latter. (Victor's patch even had to change the locale coercion tests because it broke the isolated mode behaviour described in the PEP)

I was trying to be nice about it, but given that Victor is starting to just go ahead and change things further, I'm going to go with the hardline veto option: make PEP 538 work the it is described in the PEP and stop trying to change it on an arbitrary whim without writing a new PEP to overrule the original one.