/usr/include/gromacs/options/ is in libgromacs-dev 2018.1-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/gromacs/options/abstractoption.h
/usr/include/gromacs/options/abstractsection.h
/usr/include/gromacs/options/basicoptions.h
/usr/include/gromacs/options/filenameoption.h
/usr/include/gromacs/options/filenameoptionmanager.h
/usr/include/gromacs/options/ioptionsbehavior.h
/usr/include/gromacs/options/ioptionscontainer.h
/usr/include/gromacs/options/ioptionscontainerwithsections.h
/usr/include/gromacs/options/isectionstorage.h
/usr/include/gromacs/options/ivaluestore.h
/usr/include/gromacs/options/optionfiletype.h
/usr/include/gromacs/options/optionflags.h
/usr/include/gromacs/options/options.h
/usr/include/gromacs/options/optionsection.h
/usr/include/gromacs/options/repeatingsection.h
/usr/include/gromacs/options/timeunitmanager.h
/usr/include/gromacs/options/valuestore.h