/usr/include/dune/pdelab/constraints/ is in libdune-pdelab-dev 2.5.0~rc1-2build1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/dune/pdelab/constraints/common/
/usr/include/dune/pdelab/constraints/common/constraints.hh
/usr/include/dune/pdelab/constraints/common/constraintsparameters.hh
/usr/include/dune/pdelab/constraints/common/constraintstransformation.hh
/usr/include/dune/pdelab/constraints/conforming.hh
/usr/include/dune/pdelab/constraints/hangingnode.hh
/usr/include/dune/pdelab/constraints/hangingnodemanager.hh
/usr/include/dune/pdelab/constraints/interiornode.hh
/usr/include/dune/pdelab/constraints/noconstraints.hh
/usr/include/dune/pdelab/constraints/p0.hh
/usr/include/dune/pdelab/constraints/p0ghost.hh
/usr/include/dune/pdelab/constraints/raviartthomas0.hh