On Fri, 9 Aug 2024, John Gardner wrote:

quoted

So ideally, the fallback for "?0" should be "+0 or -0", which is
much more readable and less ambiguous than "+-0" or "+/-0".

quoted

For approximating ? in ASCII, is there some reason \z_+0 hasn't been
considered?

I had forgotten that approach.

The problem of discussing signed zeros goes beyond way beyond nextup.3.

I had a discussion with someone wanting to use the UTF-8 character that 
renders like \z_+0 inside comments in a C program to better document 
branch cuts for complex numbers. I was not enthused because I use an 
editor that does not understand UTF-8.

But I think the fact that "...+0 and -0" are used already makes the 
argument for consistency pretty compelling.

My 2c - Damian