/usr/include/ITK-4.5/vnl/algo/ is in libinsighttoolkit4-dev 4.5.0-3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/ITK-4.5/vnl/algo/dll.h
/usr/include/ITK-4.5/vnl/algo/vnl_adaptsimpson_integral.h
/usr/include/ITK-4.5/vnl/algo/vnl_adjugate.h
/usr/include/ITK-4.5/vnl/algo/vnl_adjugate.txx
/usr/include/ITK-4.5/vnl/algo/vnl_algo_fwd.h
/usr/include/ITK-4.5/vnl/algo/vnl_amoeba.h
/usr/include/ITK-4.5/vnl/algo/vnl_bracket_minimum.h
/usr/include/ITK-4.5/vnl/algo/vnl_brent.h
/usr/include/ITK-4.5/vnl/algo/vnl_brent_minimizer.h
/usr/include/ITK-4.5/vnl/algo/vnl_chi_squared.h
/usr/include/ITK-4.5/vnl/algo/vnl_chi_squared.txx
/usr/include/ITK-4.5/vnl/algo/vnl_cholesky.h
/usr/include/ITK-4.5/vnl/algo/vnl_complex_eigensystem.h
/usr/include/ITK-4.5/vnl/algo/vnl_complex_generalized_schur.h
/usr/include/ITK-4.5/vnl/algo/vnl_conjugate_gradient.h
/usr/include/ITK-4.5/vnl/algo/vnl_convolve.h
/usr/include/ITK-4.5/vnl/algo/vnl_convolve.txx
/usr/include/ITK-4.5/vnl/algo/vnl_cpoly_roots.h
/usr/include/ITK-4.5/vnl/algo/vnl_determinant.h
/usr/include/ITK-4.5/vnl/algo/vnl_determinant.txx
/usr/include/ITK-4.5/vnl/algo/vnl_discrete_diff.h
/usr/include/ITK-4.5/vnl/algo/vnl_fft.h
/usr/include/ITK-4.5/vnl/algo/vnl_fft_1d.h
/usr/include/ITK-4.5/vnl/algo/vnl_fft_1d.txx
/usr/include/ITK-4.5/vnl/algo/vnl_fft_2d.h
/usr/include/ITK-4.5/vnl/algo/vnl_fft_2d.txx
/usr/include/ITK-4.5/vnl/algo/vnl_fft_base.h
/usr/include/ITK-4.5/vnl/algo/vnl_fft_base.txx
/usr/include/ITK-4.5/vnl/algo/vnl_fft_prime_factors.h
/usr/include/ITK-4.5/vnl/algo/vnl_fft_prime_factors.txx
/usr/include/ITK-4.5/vnl/algo/vnl_fit_parabola.h
/usr/include/ITK-4.5/vnl/algo/vnl_gaussian_kernel_1d.h
/usr/include/ITK-4.5/vnl/algo/vnl_generalized_eigensystem.h
/usr/include/ITK-4.5/vnl/algo/vnl_generalized_schur.h
/usr/include/ITK-4.5/vnl/algo/vnl_lbfgs.h
/usr/include/ITK-4.5/vnl/algo/vnl_lbfgsb.h
/usr/include/ITK-4.5/vnl/algo/vnl_ldl_cholesky.h
/usr/include/ITK-4.5/vnl/algo/vnl_levenberg_marquardt.h
/usr/include/ITK-4.5/vnl/algo/vnl_lsqr.h
/usr/include/ITK-4.5/vnl/algo/vnl_matrix_inverse.h
/usr/include/ITK-4.5/vnl/algo/vnl_matrix_inverse.txx
/usr/include/ITK-4.5/vnl/algo/vnl_matrix_update.h
/usr/include/ITK-4.5/vnl/algo/vnl_netlib.h
/usr/include/ITK-4.5/vnl/algo/vnl_orthogonal_complement.h
/usr/include/ITK-4.5/vnl/algo/vnl_orthogonal_complement.txx
/usr/include/ITK-4.5/vnl/algo/vnl_powell.h
/usr/include/ITK-4.5/vnl/algo/vnl_qr.h
/usr/include/ITK-4.5/vnl/algo/vnl_qr.txx
/usr/include/ITK-4.5/vnl/algo/vnl_real_eigensystem.h
/usr/include/ITK-4.5/vnl/algo/vnl_rnpoly_solve.h
/usr/include/ITK-4.5/vnl/algo/vnl_scatter_3x3.h
/usr/include/ITK-4.5/vnl/algo/vnl_scatter_3x3.txx
/usr/include/ITK-4.5/vnl/algo/vnl_simpson_integral.h
/usr/include/ITK-4.5/vnl/algo/vnl_solve_qp.h
/usr/include/ITK-4.5/vnl/algo/vnl_sparse_lm.h
/usr/include/ITK-4.5/vnl/algo/vnl_sparse_lu.h
/usr/include/ITK-4.5/vnl/algo/vnl_sparse_symmetric_eigensystem.h
/usr/include/ITK-4.5/vnl/algo/vnl_svd.h
/usr/include/ITK-4.5/vnl/algo/vnl_svd.txx
/usr/include/ITK-4.5/vnl/algo/vnl_svd_economy.h
/usr/include/ITK-4.5/vnl/algo/vnl_svd_economy.txx
/usr/include/ITK-4.5/vnl/algo/vnl_svd_fixed.h
/usr/include/ITK-4.5/vnl/algo/vnl_svd_fixed.txx
/usr/include/ITK-4.5/vnl/algo/vnl_symmetric_eigensystem.h
/usr/include/ITK-4.5/vnl/algo/vnl_symmetric_eigensystem.txx