/usr/bin/w3mman is in w3m 0.5.3-36build1.
This file is owned by root:root, with mode 0o755.
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 | #!/usr/bin/perl
@W3M = split(' ', $ENV{'W3MMAN_W3M'} || 'w3m');
$ENV{'W3MMAN_MAN'} ||= '/usr/bin/man';
$SCRIPT = 'file:///$LIB/w3mman2html.cgi';
sub usage {
  ($_ = $0) =~ s@.*/@@;
  print STDERR "$_ [-M <path>] [[<section>] <command>]\n";
  print STDERR "$_ [-M <path>] [-k <keyword>]\n";
  print STDERR "$_ [-l <file>]\n";
  exit 1;
}
$query = "";
while (@ARGV) {
  $_ = shift @ARGV;
  if (/^-M$/) {
    @ARGV || &usage();
    $ENV{'MANPATH'} = shift @ARGV;
  } elsif (/^-k$/) {
    @ARGV || &usage();
    $query = "?keyword=" . &form_encode(shift @ARGV);
  } elsif (/^-l$/) {
    @ARGV || &usage(); 
    $query = "?quit=ok&local=" . &form_encode(shift @ARGV);
    $query .= "&pwd=" . &form_encode($ENV{'PWD'});
  } elsif (/^-/) {
    &usage();
  } elsif (/^\d/ || $_ eq 'n') {
    @ARGV || &usage();
    $query = "?quit=ok&man=" . &form_encode(shift @ARGV);
    $query .= "§ion=" . &form_encode($_);
  } else {
    $query = "?quit=ok&man=" . &form_encode($_);
  }
}
exec @W3M, "$SCRIPT$query";
sub form_encode {
  local($_) = @_;
  s/[\000-\040\+:#?&%<>"\177-\377]/sprintf('%%%02X', unpack('C', $&))/eg;
  return $_;
}
 |