/usr/include/itpp/base/ is in libitpp-dev 4.3.1-2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/itpp/base/algebra/
/usr/include/itpp/base/algebra/cholesky.h
/usr/include/itpp/base/algebra/det.h
/usr/include/itpp/base/algebra/eigen.h
/usr/include/itpp/base/algebra/inv.h
/usr/include/itpp/base/algebra/lapack.h
/usr/include/itpp/base/algebra/ls_solve.h
/usr/include/itpp/base/algebra/lu.h
/usr/include/itpp/base/algebra/qr.h
/usr/include/itpp/base/algebra/schur.h
/usr/include/itpp/base/algebra/svd.h
/usr/include/itpp/base/array.h
/usr/include/itpp/base/base_exports.h
/usr/include/itpp/base/bessel/
/usr/include/itpp/base/bessel.h
/usr/include/itpp/base/bessel/bessel_internal.h
/usr/include/itpp/base/binary.h
/usr/include/itpp/base/binfile.h
/usr/include/itpp/base/blas.h
/usr/include/itpp/base/circular_buffer.h
/usr/include/itpp/base/converters.h
/usr/include/itpp/base/copy_vector.h
/usr/include/itpp/base/factory.h
/usr/include/itpp/base/fastmath.h
/usr/include/itpp/base/gf2mat.h
/usr/include/itpp/base/help_functions.h
/usr/include/itpp/base/itassert.h
/usr/include/itpp/base/itcompat.h
/usr/include/itpp/base/itfile.h
/usr/include/itpp/base/ittypes.h
/usr/include/itpp/base/mat.h
/usr/include/itpp/base/matfunc.h
/usr/include/itpp/base/math/
/usr/include/itpp/base/math/elem_math.h
/usr/include/itpp/base/math/error.h
/usr/include/itpp/base/math/integration.h
/usr/include/itpp/base/math/log_exp.h
/usr/include/itpp/base/math/min_max.h
/usr/include/itpp/base/math/misc.h
/usr/include/itpp/base/math/trig_hyp.h
/usr/include/itpp/base/operators.h
/usr/include/itpp/base/parser.h
/usr/include/itpp/base/random.h
/usr/include/itpp/base/random_dsfmt.h
/usr/include/itpp/base/smat.h
/usr/include/itpp/base/sort.h
/usr/include/itpp/base/specmat.h
/usr/include/itpp/base/stack.h
/usr/include/itpp/base/svec.h
/usr/include/itpp/base/timing.h
/usr/include/itpp/base/vec.h