/usr/ is in ubuntu-release-upgrader-core 1:16.04.25.
This file is owned by root:root, with mode 0o755.
..
/usr/share/polkit-1/
/usr/share/polkit-1/actions/
/usr/lib/
/usr/lib/ubuntu-release-upgrader/
/usr/lib/ubuntu-release-upgrader/do-partial-upgrade
/usr/lib/ubuntu-release-upgrader/release-upgrade-motd
/usr/share/
/usr/share/polkit-1/actions/com.ubuntu.release-upgrader.policy
/usr/share/apport/
/usr/share/apport/package-hooks/
/usr/share/apport/package-hooks/source_ubuntu-release-upgrader.py
/usr/share/doc/
/usr/share/doc/ubuntu-release-upgrader-core/
/usr/share/doc/ubuntu-release-upgrader-core/AUTHORS
/usr/share/doc/ubuntu-release-upgrader-core/copyright
/usr/share/doc/ubuntu-release-upgrader-core/README
/usr/share/man/
/usr/share/man/man8/
/usr/share/man/man8/do-release-upgrade.8.gz
/usr/share/ubuntu-release-upgrader/
/usr/share/ubuntu-release-upgrader/removal_blacklist.cfg
/usr/share/ubuntu-release-upgrader/DistUpgrade.cfg
/usr/share/ubuntu-release-upgrader/additional_pkgs.cfg
/usr/share/ubuntu-release-upgrader/demoted.cfg
/usr/share/ubuntu-release-upgrader/mirrors.cfg
/usr/bin/
/usr/bin/do-release-upgrade
/usr/lib/ubuntu-release-upgrader/check-new-release
/usr/share/doc/ubuntu-release-upgrader-core/changelog.gz