/usr/include/dune/grid/alugrid/2d/ is in libdune-grid-dev 2.2.1-2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/dune/grid/alugrid/2d/alu2dgridfactory.cc
/usr/include/dune/grid/alugrid/2d/alu2dgridfactory.hh
/usr/include/dune/grid/alugrid/2d/alu2dinclude.hh
/usr/include/dune/grid/alugrid/2d/alugrid.hh
/usr/include/dune/grid/alugrid/2d/bndprojection.hh
/usr/include/dune/grid/alugrid/2d/capabilities.hh
/usr/include/dune/grid/alugrid/2d/datahandle.hh
/usr/include/dune/grid/alugrid/2d/entity.hh
/usr/include/dune/grid/alugrid/2d/entity_imp.cc
/usr/include/dune/grid/alugrid/2d/entityseed.hh
/usr/include/dune/grid/alugrid/2d/geometry.hh
/usr/include/dune/grid/alugrid/2d/geometry_imp.cc
/usr/include/dune/grid/alugrid/2d/grid.hh
/usr/include/dune/grid/alugrid/2d/grid_imp.cc
/usr/include/dune/grid/alugrid/2d/indexsets.hh
/usr/include/dune/grid/alugrid/2d/intersection.cc
/usr/include/dune/grid/alugrid/2d/intersection.hh
/usr/include/dune/grid/alugrid/2d/intersection_imp.cc
/usr/include/dune/grid/alugrid/2d/iterator.hh
/usr/include/dune/grid/alugrid/2d/iterator_imp.cc