/usr/include/linbox/algorithms/polynomial-matrix/ is in liblinbox-dev 1.4.2-5build1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/linbox/algorithms/polynomial-matrix/matpoly-add-domain.h
/usr/include/linbox/algorithms/polynomial-matrix/matpoly-mult-fft-multiprecision.inl
/usr/include/linbox/algorithms/polynomial-matrix/matpoly-mult-fft-recint.inl
/usr/include/linbox/algorithms/polynomial-matrix/matpoly-mult-fft-wordsize-fast.inl
/usr/include/linbox/algorithms/polynomial-matrix/matpoly-mult-fft-wordsize-three-primes.inl
/usr/include/linbox/algorithms/polynomial-matrix/matpoly-mult-fft-wordsize.inl
/usr/include/linbox/algorithms/polynomial-matrix/matpoly-mult-fft.h
/usr/include/linbox/algorithms/polynomial-matrix/matpoly-mult-kara.h
/usr/include/linbox/algorithms/polynomial-matrix/matpoly-mult-naive.h
/usr/include/linbox/algorithms/polynomial-matrix/order-basis.h
/usr/include/linbox/algorithms/polynomial-matrix/polynomial-fft-transform-simd.inl
/usr/include/linbox/algorithms/polynomial-matrix/polynomial-fft-transform.h
/usr/include/linbox/algorithms/polynomial-matrix/polynomial-fft-transform.inl
/usr/include/linbox/algorithms/polynomial-matrix/polynomial-matrix-domain.h
/usr/include/linbox/algorithms/polynomial-matrix/simd.h