/usr/lib/dpkg/methods/floppy/install is in dselect 1.18.25.
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 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 | #!/bin/sh
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
set -e
vardir="$1"
method=$2
option=$3
cd "$vardir/methods/floppy"
mountpoint="$vardir/methods/mnt"
. ./shvar.$option
help () {
	echo '
Now I need the disks containing the packages to be installed.
I shall keep telling you what is left to be done, in case that
is helpful deciding which floppy to use.'
}
help
xit=1
trap '
	if [ -n "$umount" ]
	then
		umount "$umount"
	fi
	exit $xit
' 0
while [ -z "$goconfigure" ]
do
	yet="`dpkg --admindir $vardir --yet-to-unpack`"
	if [ -z "$yet" ]
	then
		echo '
All packages unpacked, going on to configure them.
'
		goconfigure=1
		continue
	fi
	echo '
Packages yet to be unpacked:'
	echo "$yet"
	dpkg-split -l
	echo -n '
Insert a disk containing *.deb files, or type q to quit.  '
	read response
	case "$response" in
	[Qq] | [Qq][Uu][Ii][Tt] )
		goconfigure=1
		;;
	* )
		umount="$defaultfloppy"
		if mount -rt "$defaultfstype" "$defaultfloppy" "$mountpoint"
		then
			echo
			dpkg --admindir $vardir --unpack -GROEB "$mountpoint" || true
			umount "$defaultfloppy"
		fi
		umount=""
		;;
	esac
done
if ! [ -z "$yet" ]
then
	response=""
	while [ -z "$response" ]
	do
		echo -n '
Not all the packages have yet been unpacked.  Shall I try to
proceed with configuration anyay ?  If any of the packages which
have been unpacked so far depend on any that haven'\''t then you'\''ll
see error messages; on the other hand if you say no those packages that
could have been configured will not be.   (y/n)  '
		read response
		case "$response" in
		[Nn]* )
			echo '
OK.  Be sure to come back to this, because unpacked-but-not-configured
packages are not in general useable.  Alternatively, use the Configure
option on the dselect menu.
'
			exit 1
			;;
		[Yy]* )
			;;
		* )
			response=""
			;;
		esac
	done
fi
dpkg --admindir $vardir --configure --pending
xit=0
 |