/usr/share/ is in cantor-backend-octave 4:17.12.3-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/cantor/
/usr/share/cantor/octavebackend/
/usr/share/cantor/octavebackend/cantor_eigenvectors.m
/usr/share/cantor/octavebackend/cantor_plot2d.m
/usr/share/cantor/octavebackend/cantor_plot3d.m
/usr/share/cantor/octavebackend/cantor_print.m
/usr/share/config.kcfg/
/usr/share/config.kcfg/octavebackend.kcfg
/usr/share/doc/
/usr/share/doc/cantor-backend-octave/
/usr/share/doc/cantor-backend-octave/copyright
/usr/share/icons/
/usr/share/icons/hicolor/
/usr/share/icons/hicolor/48x48/
/usr/share/icons/hicolor/48x48/apps/
/usr/share/icons/hicolor/48x48/apps/octavebackend.png
/usr/share/doc/cantor-backend-octave/changelog.Debian.gz