/usr/include/linbox/algorithms/gauss/ is in liblinbox-dev 1.4.2-5build1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/linbox/algorithms/gauss/gauss-det.inl
/usr/include/linbox/algorithms/gauss/gauss-elim-gf2.inl
/usr/include/linbox/algorithms/gauss/gauss-elim.inl
/usr/include/linbox/algorithms/gauss/gauss-gf2.inl
/usr/include/linbox/algorithms/gauss/gauss-nullspace.inl
/usr/include/linbox/algorithms/gauss/gauss-pivot-gf2.inl
/usr/include/linbox/algorithms/gauss/gauss-pivot.inl
/usr/include/linbox/algorithms/gauss/gauss-rank-gf2.inl
/usr/include/linbox/algorithms/gauss/gauss-rank.inl
/usr/include/linbox/algorithms/gauss/gauss-solve-gf2.inl
/usr/include/linbox/algorithms/gauss/gauss-solve.inl
/usr/include/linbox/algorithms/gauss/gauss.inl