Confirmed the warning occurring with
/usr/share/man $ LC_ALL=en_US.UTF-8 MANROFFSEQ='' MANWIDTH=80 man --warnings -E UTF-8 -l -Tutf8 -Z man1/pear.1.gz > /dev/null
:230: warning: macro `PS' not defined
Running this on the fixed file causes no warning to be displayed and the content is parsed/displayed the same as before.
Outputs:
We use "Example begin" (
.EX
)/"Example end" (.EE
) instead, see groff_man(7).