/usr/share/zsh/functions/Misc/mere is in zsh-common 5.0.7-5.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 | # read a man page
setopt localoptions extendedglob
local manual="$1" col=col terminal=man magic line
# /usr/bin/col on SunOS 4 doesn't support -x.
if [[ -x /usr/5bin/col ]]; then
  col=/usr/5bin/col;
fi
# SunOS 5 has no `man' terminal.
if [[ -d /usr/share/lib/nterm &&
    ! -e /usr/share/lib/nterm/tab.$terminal ]]; then
  terminal=lp;
fi
# HP-UX has no `man' terminal.
if [[ -d /usr/share/lib/term &&
    ! -e /usr/share/lib/term/tab$terminal ]]; then
  terminal=lp;
fi
# IRIX has no `man' terminal.
if [[ -d /usr/lib/nterm &&
    ! -e /usr/lib/nterm/tab.$terminal ]]; then
  terminal=lp;
fi
# Unixware has no `man' terminal.
if [[ -d /usr/ucblib/doctools/nterm &&
    ! -e /usr/ucblib/doctools/nterm/tab.$terminal ]]; then
  terminal=lp;
fi
# Solaris has SGML manuals.
if [[ -f /usr/lib/sgml/sgml2roff ]] && 
   [[ "$(read -er < $manual)" = "<!DOCTYPE"* ]]; then
  /usr/lib/sgml/sgml2roff $manual | {
    read -r line
    if [[ $line = ".so "* ]]; then
      # There is no cascading .so directive.
      # On Solaris 7, at least.
      /usr/lib/sgml/sgml2roff ${line#.so }
    else
      print -lr - "$line"
      cat
    fi
  }
else
  read -u0 -k 2 magic < $manual
  case $magic in
  $'\037\235') zcat $manual;;
  $'\037\213') gzip -dc $manual;;
  *) cat $manual;;
  esac
fi | (
  # cd is required to work soelim called by nroff.
  case $manual in
  */man/man*/*) cd ${manual:h:h};;
  */man/sman*/*) cd ${manual:h:h};;
  esac
  read -r line
  # The first line beginning with '\" shows preprocessors.
  # Unknown preprocessors is ignored.
  if [[ $line = "'\\\" "* ]]; then
    typeset -A filter
    filter=(
      e neqn
      g grap
      p pic
      r refer
      t tbl
      v vgrind
    )
    eval ${(j:|:)${${(s::)line#\'\\\" }//(#m)?/$filter[$MATCH]}}
  elif [[ $line = "'\\\"! "* ]]; then
    typeset -A filter
    filter=(
      eqn neqn
    )
    eval ${(j:|:)${${${${(s:|:)line#\'\\\"! }# ##}% ##}//(#m)*/$filter[$MATCH]}}
  else
    print -lr - "$line"
    cat
  fi |
  nroff -T$terminal -man | $col -x
) |
${=MANPAGER:-${PAGER:-more}} -s
 |