/usr/include/ is in librelion-dev-common 1.4+dfsg-3ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/relion-1.4/
/usr/include/relion-1.4/relion.h
/usr/include/relion-1.4/src/
/usr/include/relion-1.4/src/Healpix_2.15a/
/usr/include/relion-1.4/src/Healpix_2.15a/arr.h
/usr/include/relion-1.4/src/Healpix_2.15a/cxxutils.h
/usr/include/relion-1.4/src/Healpix_2.15a/datatypes.h
/usr/include/relion-1.4/src/Healpix_2.15a/geom_utils.h
/usr/include/relion-1.4/src/Healpix_2.15a/healpix_base.h
/usr/include/relion-1.4/src/Healpix_2.15a/lsconstants.h
/usr/include/relion-1.4/src/Healpix_2.15a/message_error.h
/usr/include/relion-1.4/src/Healpix_2.15a/openmp_support.h
/usr/include/relion-1.4/src/Healpix_2.15a/pointing.h
/usr/include/relion-1.4/src/Healpix_2.15a/vec3.h
/usr/include/relion-1.4/src/args.h
/usr/include/relion-1.4/src/assembly.h
/usr/include/relion-1.4/src/autopicker.h
/usr/include/relion-1.4/src/backprojector.h
/usr/include/relion-1.4/src/complex.h
/usr/include/relion-1.4/src/ctf.h
/usr/include/relion-1.4/src/ctffind_runner.h
/usr/include/relion-1.4/src/displayer.h
/usr/include/relion-1.4/src/error.h
/usr/include/relion-1.4/src/euler.h
/usr/include/relion-1.4/src/exp_model.h
/usr/include/relion-1.4/src/fftw.h
/usr/include/relion-1.4/src/filename.h
/usr/include/relion-1.4/src/funcs.h
/usr/include/relion-1.4/src/gcc_version.h
/usr/include/relion-1.4/src/gui_entries.h
/usr/include/relion-1.4/src/gui_jobwindow.h
/usr/include/relion-1.4/src/gui_mainwindow.h
/usr/include/relion-1.4/src/healpix_sampling.h
/usr/include/relion-1.4/src/image.h
/usr/include/relion-1.4/src/macros.h
/usr/include/relion-1.4/src/mask.h
/usr/include/relion-1.4/src/matrix1d.h
/usr/include/relion-1.4/src/matrix2d.h
/usr/include/relion-1.4/src/memory.h
/usr/include/relion-1.4/src/metadata_container.h
/usr/include/relion-1.4/src/metadata_label.h
/usr/include/relion-1.4/src/metadata_table.h
/usr/include/relion-1.4/src/ml_model.h
/usr/include/relion-1.4/src/ml_optimiser.h
/usr/include/relion-1.4/src/multidim_array.h
/usr/include/relion-1.4/src/numerical_recipes.h
/usr/include/relion-1.4/src/parallel.h
/usr/include/relion-1.4/src/particle_polisher.h
/usr/include/relion-1.4/src/particle_sorter.h
/usr/include/relion-1.4/src/postprocessing.h
/usr/include/relion-1.4/src/preprocessing.h
/usr/include/relion-1.4/src/projector.h
/usr/include/relion-1.4/src/rwIMAGIC.h
/usr/include/relion-1.4/src/rwMRC.h
/usr/include/relion-1.4/src/rwSPIDER.h
/usr/include/relion-1.4/src/strings.h
/usr/include/relion-1.4/src/symmetries.h
/usr/include/relion-1.4/src/tabfuncs.h
/usr/include/relion-1.4/src/time.h
/usr/include/relion-1.4/src/transformations.h