/usr/share/konwert/devel/mkUTF8-charset is in konwert-dev 1.8-11.2build2.
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 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 90 91 | #!/usr/bin/perl
$charset_utf8 = shift;
$utf8_charset = shift;
foreach (map {chr} 32 .. 126) {$charset_utf8{$_} = $_}
if ($charset_utf8 ne "ascii")
{
	open CHARSET_UTF8, $charset_utf8;
	while (<CHARSET_UTF8>)
	{
		$charset_utf8{$2} = $1
			if /^\t(\S+)\t(\S+)$/ && !exists $charset_utf8{$2};
	}
	close CHARSET_UTF8;
}
open UTF8_CHARSET, $utf8_charset;
while (<UTF8_CHARSET>)
{
	@alt = split;
	$utf8 = shift @alt;
	next if exists $charset_utf8{$utf8};
	@jest = ();
	foreach (@alt)
	{
		$wariant = s/^((?:.|\\.)+)\\V(.+)$/$1/ ? $2 : "";
		@znakiist = /[^\200-\377]|[\300-\377][\200-\277]+/g;
		if (!grep {!exists $charset_utf8{$_}} @znakiist)
		{
			s/^((?:.|\\.)+)\\\}.*?$/$1/;
			@znaki = /[^\200-\377]|[\300-\377][\200-\277]+/g;
			$jeden = @znaki == 1 || /^\\[^!]$/;
			unless
			(
				$jest[$jeden]{$wariant} ||
				$jest[$jeden]{""} ||
				$jest[1]{$wariant}
			)
			{
				$utf8_charset[$jeden]{$wariant}{$utf8} =
				join "", map {$charset_utf8{$_}} @znaki
				if $wariant ne "" || /[\300-\377]/
				|| $utf8 eq "\357\277\275";
				last if $jeden && $wariant eq "";
				$jest[$jeden]{$wariant} = 1;
			}
		}
	}
}
close UTF8_CHARSET;
$zastap = exists $charset_utf8{"\357\277\275"} ?
	$charset_utf8{"\357\277\275"}
:
	$utf8_charset[1]{""}{"\357\277\275"};
delete $utf8_charset[1]{""}{"\357\277\275"};
sub wypisz (\%)
{
	my ($utf8_charset) = @_;
	foreach $utf8 (sort keys %$utf8_charset)
	{
		$_ = "\t$utf8\t$$utf8_charset{$utf8}\n";
		s/'/'\\''/g;
		print;
	}
}
foreach $jeden (0, 1)
{
	foreach $wariant (sort grep {$_ ne ""} keys %{$utf8_charset[$jeden]})
	{
		print "VARIANT${\(\"\",\"1\")[$jeden]}_$wariant='\n";
		wypisz %{$utf8_charset[$jeden]{$wariant}};
		print "' ";
	}
}
if ($charset_utf8 ne "ascii")
{
	print "APPROX='\n";
	wypisz %{$utf8_charset[0]{""}};
	print "' APPROX1='\n";
	wypisz %{$utf8_charset[1]{""}};
	print "' ";
}
$zastap =~ s/'/'\\''/g;
print "REPLACE='${zastap}'";
 |