/usr/lib/ is in update-notifier-common 3.192.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/update-notifier/
/usr/lib/update-notifier/apt-cdrom-check
/usr/lib/update-notifier/apt_check.py
/usr/lib/update-notifier/backend_helper.py
/usr/lib/update-notifier/cddistupgrader
/usr/lib/update-notifier/package-data-downloader
/usr/lib/update-notifier/package-system-locked
/usr/lib/update-notifier/update-motd-fsck-at-reboot
/usr/lib/update-notifier/update-motd-hwe-eol
/usr/lib/update-notifier/update-motd-reboot-required
/usr/lib/update-notifier/update-motd-updates-available
/usr/lib/update-notifier/apt-check