/usr/ is in cantor-backend-sage 4:4.13.0-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/icons/hicolor/48x48/apps/sagebackend.png
/usr/share/kde4/
/usr/share/kde4/services/
/usr/share/kde4/services/cantor/
/usr/lib/
/usr/lib/kde4/
/usr/lib/kde4/cantor_sagebackend.so
/usr/share/
/usr/share/icons/
/usr/share/icons/hicolor/
/usr/share/icons/hicolor/48x48/
/usr/share/icons/hicolor/48x48/apps/
/usr/share/kde4/services/cantor/sagebackend.desktop
/usr/share/kde4/apps/
/usr/share/kde4/apps/cantor/
/usr/share/kde4/apps/cantor/sagebackend/
/usr/share/kde4/apps/cantor/sagebackend/keywords.xml
/usr/share/kde4/config/
/usr/share/kde4/config/cantor_sage.knsrc
/usr/share/kde4/config.kcfg/
/usr/share/kde4/config.kcfg/sagebackend.kcfg
/usr/share/doc/
/usr/share/doc/cantor-backend-sage/
/usr/share/doc/cantor-backend-sage/copyright
/usr/share/doc/cantor-backend-sage/README.Debian
/usr/share/doc/cantor-backend-sage/changelog.Debian.gz