/usr/include/dune/grid/io/file/dgfparser/blocks/ is in libdune-grid-dev 2.4.1-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/dune/grid/io/file/dgfparser/blocks/basic.hh
/usr/include/dune/grid/io/file/dgfparser/blocks/boundarydom.hh
/usr/include/dune/grid/io/file/dgfparser/blocks/boundaryseg.hh
/usr/include/dune/grid/io/file/dgfparser/blocks/cube.hh
/usr/include/dune/grid/io/file/dgfparser/blocks/dim.hh
/usr/include/dune/grid/io/file/dgfparser/blocks/general.hh
/usr/include/dune/grid/io/file/dgfparser/blocks/gridparameter.hh
/usr/include/dune/grid/io/file/dgfparser/blocks/interval.hh
/usr/include/dune/grid/io/file/dgfparser/blocks/periodicfacetrans.hh
/usr/include/dune/grid/io/file/dgfparser/blocks/projection.hh
/usr/include/dune/grid/io/file/dgfparser/blocks/simplex.hh
/usr/include/dune/grid/io/file/dgfparser/blocks/simplexgeneration.hh
/usr/include/dune/grid/io/file/dgfparser/blocks/vertex.hh