/usr/share/gromacs/ is in libgromacs-dev 2018.1-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/gromacs/cmake/
/usr/share/gromacs/cmake/gromacs/
/usr/share/gromacs/cmake/gromacs/gromacs-config-version.cmake
/usr/share/gromacs/cmake/gromacs/gromacs-config.cmake
/usr/share/gromacs/cmake/gromacs/libgromacs-release.cmake
/usr/share/gromacs/cmake/gromacs/libgromacs.cmake
/usr/share/gromacs/cmake/gromacs_d/
/usr/share/gromacs/cmake/gromacs_d/gromacs_d-config-version.cmake
/usr/share/gromacs/cmake/gromacs_d/gromacs_d-config.cmake
/usr/share/gromacs/cmake/gromacs_d/libgromacs-release.cmake
/usr/share/gromacs/cmake/gromacs_d/libgromacs.cmake
/usr/share/gromacs/template/
/usr/share/gromacs/template/CMakeLists.txt
/usr/share/gromacs/template/Makefile.pkg
/usr/share/gromacs/template/README
/usr/share/gromacs/template/cmake/
/usr/share/gromacs/template/cmake/FindGROMACS.cmake
/usr/share/gromacs/template/template.cpp