/usr/include/linbox/solutions/ is in liblinbox-dev 1.3.2-1.1+b1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/linbox/solutions/charpoly.h
/usr/include/linbox/solutions/det.h
/usr/include/linbox/solutions/getentry.h
/usr/include/linbox/solutions/is-positive-definite.h
/usr/include/linbox/solutions/is-positive-semidefinite.h
/usr/include/linbox/solutions/methods.h
/usr/include/linbox/solutions/minpoly.h
/usr/include/linbox/solutions/nullspace.h
/usr/include/linbox/solutions/rank.h
/usr/include/linbox/solutions/smith-form.h
/usr/include/linbox/solutions/solve.h
/usr/include/linbox/solutions/trace.h
/usr/include/linbox/solutions/valence.h