/usr/share/konwert/devel/UTF8-ascii is in konwert-dev 1.8-11.2build2.
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 | if [ "$FILTERM" = out ]
then
	NPOJED=
else
	NPOJED=1
fi
FORMAT=
HTMLCHAR=
POPRAWKI=
for A in $ARG
do
	case "$A" in
	(1)               NPOJED=;;
	(html)            FORMAT=html;;
	(htmldec|htmlhex) FORMAT=html; HTMLCHAR=${A#html};;
	(tex)             FORMAT=tex;;
	(*)
		if [ -x "${0%/*}/../aux/argcharset/$A" ]
		then
			POPRAWKI=${POPRAWKI:+$POPRAWKI | }${0%/*}/../aux/argcharset/$A
		fi
		VARIANT=VARIANT_$A; APPROX="${!VARIANT} $APPROX"
		VARIANT=VARIANT1_$A; APPROX1="${!VARIANT} $APPROX1"
		;;
	esac
done
if [ "$POPRAWKI" ]
then
	"$SHELL" -c "$POPRAWKI"
else
	cat
fi |
case "$FORMAT" in
(html)
	"${0%/*}/../aux/fixmeta" us-ascii |
	if [ "$HTMLCHAR" ]
	then
		"${0%/*}/UTF8-html$HTMLCHAR"
	else
		trs -e '\}\[@&<>\] @' \
			${NPOJED:+-e} ${NPOJED:+"$APPROX"} \
			-e "$APPROX1" \
			${NPOJED:+-f} ${NPOJED:+"${0%/*}/../aux/UTF8-ascii"} \
			-f "${0%/*}/../aux/UTF8-ascii1" \
			-e "\300\-\377 ${REPLACE:-?} \200\-\277 \!" |
		trs -e '@@ @ @& & @< < @> > & & < < > >'
	fi
	;;
(tex)
	trs -e '\}\[@\#$%&\\^_{|}~\] @' \
		-f "${0%/*}/../aux/UTF8-tex" \
		-e "$APPROX" \
		-e "$APPROX1" \
		-f "${0%/*}/../aux/UTF8-ascii" \
		-f "${0%/*}/../aux/UTF8-ascii1" \
		-e "\300\-\377 ${REPLACE:-?} \200\-\277 \!" |
	trs -e '@@ @ @\# \# @$ $ @% % @& & @\\ \\ @^ ^ @_ _ @{ { @| | @} } @~ ~
\# \\\# $ \\$ % \\% & \\& \\ $\\backslash$ ^ \\^{} _ \\_ { \\{ | $|$ } \\} ~ \\~{}'
	;;
(*)
	trs ${NPOJED:+-e} ${NPOJED:+"$APPROX"} \
		-e "$APPROX1" \
		${NPOJED:+-f} ${NPOJED:+"${0%/*}/../aux/UTF8-ascii"} \
		-f "${0%/*}/../aux/UTF8-ascii1" \
		-e "\300\-\377 ${REPLACE:-?} \200\-\277 \!"
	;;
esac
 |