/usr/share/ is in gnome-session 3.28.1-0ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/doc/
/usr/share/doc/gnome-session/
/usr/share/doc/gnome-session/AUTHORS
/usr/share/doc/gnome-session/NEWS.gz
/usr/share/doc/gnome-session/README
/usr/share/doc/gnome-session/README.Debian
/usr/share/doc/gnome-session/copyright
/usr/share/doc/gnome-session/dbus/
/usr/share/doc/gnome-session/dbus/gnome-session.html
/usr/share/gnome-session/
/usr/share/gnome-session/sessions/
/usr/share/gnome-session/sessions/gnome.session
/usr/share/wayland-sessions/
/usr/share/wayland-sessions/gnome.desktop
/usr/share/xsessions/
/usr/share/xsessions/gnome-xorg.desktop
/usr/share/doc/gnome-session/changelog.Debian.gz
/usr/share/xsessions/gnome.desktop