/usr/ is in ubuntu-session 3.28.1-0ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/
/usr/share/doc/
/usr/share/doc/ubuntu-session/
/usr/share/doc/ubuntu-session/copyright
/usr/share/gnome-session/
/usr/share/gnome-session/sessions/
/usr/share/gnome-session/sessions/ubuntu.session
/usr/share/gnome-shell/
/usr/share/gnome-shell/extensions/
/usr/share/gnome-shell/extensions/ubuntu-dock@ubuntu.com/
/usr/share/gnome-shell/extensions/ubuntu-dock@ubuntu.com/ubuntu-communitheme.css
/usr/share/icons/
/usr/share/lightdm/
/usr/share/lightdm/lightdm.conf.d/
/usr/share/lightdm/lightdm.conf.d/50-ubuntu.conf
/usr/share/session-migration/
/usr/share/session-migration/scripts/
/usr/share/session-migration/scripts/unity-gnome-shell-migration.17.10.py
/usr/share/wayland-sessions/
/usr/share/wayland-sessions/ubuntu-communitheme-snap-wayland.desktop
/usr/share/wayland-sessions/ubuntu-wayland.desktop
/usr/share/xsessions/
/usr/share/xsessions/ubuntu-communitheme-snap.desktop
/usr/share/xsessions/ubuntu.desktop
/usr/share/doc/ubuntu-session/changelog.Debian.gz
/usr/share/icons/communitheme