/usr/include/deal.II/numerics/ is in libdeal.ii-dev 8.1.0-6ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/deal.II/numerics/data_component_interpretation.h
/usr/include/deal.II/numerics/data_out.h
/usr/include/deal.II/numerics/data_out_dof_data.h
/usr/include/deal.II/numerics/data_out_faces.h
/usr/include/deal.II/numerics/data_out_rotation.h
/usr/include/deal.II/numerics/data_out_stack.h
/usr/include/deal.II/numerics/data_postprocessor.h
/usr/include/deal.II/numerics/derivative_approximation.h
/usr/include/deal.II/numerics/dof_output_operator.h
/usr/include/deal.II/numerics/dof_output_operator.templates.h
/usr/include/deal.II/numerics/dof_print_solver_step.h
/usr/include/deal.II/numerics/error_estimator.h
/usr/include/deal.II/numerics/fe_field_function.h
/usr/include/deal.II/numerics/fe_field_function.templates.h
/usr/include/deal.II/numerics/histogram.h
/usr/include/deal.II/numerics/matrix_tools.h
/usr/include/deal.II/numerics/point_value_history.h
/usr/include/deal.II/numerics/solution_transfer.h
/usr/include/deal.II/numerics/time_dependent.h
/usr/include/deal.II/numerics/vector_tools.h
/usr/include/deal.II/numerics/vector_tools.templates.h