/usr/share/initramfs-tools/scripts/casper-bottom/ is in casper 1.394.
This file is owned by root:root, with mode 0o755.
..
/usr/share/initramfs-tools/scripts/casper-bottom/01integrity_check
/usr/share/initramfs-tools/scripts/casper-bottom/05mountpoints
/usr/share/initramfs-tools/scripts/casper-bottom/07remove_oem_config
/usr/share/initramfs-tools/scripts/casper-bottom/12fstab
/usr/share/initramfs-tools/scripts/casper-bottom/13swap
/usr/share/initramfs-tools/scripts/casper-bottom/14locales
/usr/share/initramfs-tools/scripts/casper-bottom/15autologin
/usr/share/initramfs-tools/scripts/casper-bottom/16disable_gpt_auto_mount
/usr/share/initramfs-tools/scripts/casper-bottom/18hostname
/usr/share/initramfs-tools/scripts/casper-bottom/19keyboard
/usr/share/initramfs-tools/scripts/casper-bottom/20xconfig
/usr/share/initramfs-tools/scripts/casper-bottom/22desktop_settings
/usr/share/initramfs-tools/scripts/casper-bottom/22sslcert
/usr/share/initramfs-tools/scripts/casper-bottom/23networking
/usr/share/initramfs-tools/scripts/casper-bottom/24preseed
/usr/share/initramfs-tools/scripts/casper-bottom/25adduser
/usr/share/initramfs-tools/scripts/casper-bottom/25configure_init
/usr/share/initramfs-tools/scripts/casper-bottom/25disable_cdrom.mount
/usr/share/initramfs-tools/scripts/casper-bottom/26serialtty
/usr/share/initramfs-tools/scripts/casper-bottom/30accessibility
/usr/share/initramfs-tools/scripts/casper-bottom/31disable_update_notifier
/usr/share/initramfs-tools/scripts/casper-bottom/32disable_hibernation
/usr/share/initramfs-tools/scripts/casper-bottom/33enable_apport_crashes
/usr/share/initramfs-tools/scripts/casper-bottom/34disable_kde_services
/usr/share/initramfs-tools/scripts/casper-bottom/35fix_language_selector
/usr/share/initramfs-tools/scripts/casper-bottom/36disable_trackerd
/usr/share/initramfs-tools/scripts/casper-bottom/40install_driver_updates
/usr/share/initramfs-tools/scripts/casper-bottom/41apt_cdrom
/usr/share/initramfs-tools/scripts/casper-bottom/43disable_updateinitramfs
/usr/share/initramfs-tools/scripts/casper-bottom/44pk_allow_ubuntu
/usr/share/initramfs-tools/scripts/casper-bottom/45jackd2
/usr/share/initramfs-tools/scripts/casper-bottom/48kubuntu_disable_restart_notifications
/usr/share/initramfs-tools/scripts/casper-bottom/49kubuntu_mobile_session
/usr/share/initramfs-tools/scripts/casper-bottom/50ubiquity-bluetooth-agent
/usr/share/initramfs-tools/scripts/casper-bottom/51unity8_wizard
/usr/share/initramfs-tools/scripts/casper-bottom/52gnome_initial_setup
/usr/share/initramfs-tools/scripts/casper-bottom/53disable_unattended_upgrades
/usr/share/initramfs-tools/scripts/casper-bottom/55disable_snap_refresh