You didn't read far enough in the documentation for wait¹: "The status is returned in "$?". (Emphasis added.)

How’s that work on Windows systems?

I suspect the behavior is emulated. I'd think that it would have to be for the sake of compatibility...

1. It should probably read "wait(2)" in the perlfunc manpage, but since perl's wait() does the same thing, it doesn't much matter.

-sauoq
"My two cents aren't worth a dime.";