/lib/partman/init.d/75auto_mountpoints is in ubiquity 2.10.16.
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  | #!/bin/sh
# Only run the first time.
if [ -f /var/lib/partman/auto_mountpoints ]; then
	exit 0
fi
[ -d /var/lib/partman ] || mkdir /var/lib/partman
touch /var/lib/partman/auto_mountpoints
. /lib/partman/lib/base.sh
db_get partman/automount
if [ "$RET" = false ]; then
	exit 0
fi
if type udevadm >/dev/null 2>&1; then
	udevinfo () {
		udevadm info "$@"
	}
fi
partitions=
for dev in $DEVICES/*; do
	[ -d "$dev" ] || continue
	cd $dev
	open_dialog PARTITIONS
	while { read_line num id size type fs path name; [ "$id" ]; }; do
		if udevinfo -q env -n "$path" 2>/dev/null | egrep -q 'ID_PATH=(pci-[^-]*-)?(ieee1394|usb)'; then
			continue
		fi
		[ -f $id/detected_filesystem ] || continue
		fs=$(cat $id/detected_filesystem)
		if [ "$name" ]; then
			mountpoint="$(/usr/lib/partconf/mountpoint "$path" "$fs" "$name")"
		else
			mountpoint="$(/usr/lib/partconf/mountpoint "$path" "$fs")"
		fi
		if [ "$mountpoint" ]; then
			partitions="$partitions
$dev,$id,$fs,$mountpoint"
		fi
	done
	close_dialog
done
IFS_SAVE="$IFS"
IFS='
'
for part in $partitions; do
	IFS="$IFS_SAVE"
	dev="${part%%,*}"
	cdr="${part#*,}"
	id="${cdr%%,*}"
	cdr="${cdr#*,}"
	fs="${cdr%%,*}"
	mountpoint="${cdr#*,}"
	[ -d "$dev/$id" ] || continue
	if [ -f "$dev/$id/method" ]; then
		method="$(cat $dev/$id/method)"
		if [ "$method" ]; then
			# Already used for something else.
			continue
		fi
	fi
	echo keep >"$dev/$id/method"
	rm -f "$dev/$id/format"
	>"$dev/$id/use_filesystem"
	echo "$fs" >"$dev/$id/filesystem"
	mkdir -p "$dev/$id/options"
	echo "$mountpoint" >"$dev/$id/mountpoint"
	update_partition "$dev" "$id"
	IFS='
'
done
IFS="$IFS_SAVE"
 |