regression in TeX Live 2023 concerning some math characters

[Karl Berry]

    The fmtutil(1) man page has such a section,

I'm somewhat baffled as to how that came about.
I think help2man might have changed.

    but it doesn't mention TEXINPUTS at all.

I added one more sentence (to fmtutil.pl; man pages not regenerated yet):

    Environment:

      This script runs TeX and Metafont to generate the fmt/base file, and
      thus all normal environment variables and search path rules for TeX/MF
      apply.

Best,
Karl