/usr/ is in ubuntu-release-upgrader-qt 1:18.04.17.
This file is owned by root:root, with mode 0o755.
..
/usr/bin/
/usr/bin/kubuntu-devel-release-upgrade
/usr/share/
/usr/share/doc/
/usr/share/doc/ubuntu-release-upgrader-qt/
/usr/share/doc/ubuntu-release-upgrader-qt/copyright
/usr/share/ubuntu-release-upgrader/
/usr/share/ubuntu-release-upgrader/crashdialog.ui
/usr/share/ubuntu-release-upgrader/dialog_changes.ui
/usr/share/ubuntu-release-upgrader/dialog_conffile.ui
/usr/share/ubuntu-release-upgrader/dialog_error.ui
/usr/share/ubuntu-release-upgrader/dialog_release_notes.ui
/usr/share/ubuntu-release-upgrader/fetch-progress.ui
/usr/share/ubuntu-release-upgrader/window_main.ui
/usr/share/doc/ubuntu-release-upgrader-qt/changelog.gz