/usr/include/dolfin/fem/ is in libdolfin-dev 2017.2.0.post0-2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/dolfin/fem/Assembler.h
/usr/include/dolfin/fem/AssemblerBase.h
/usr/include/dolfin/fem/BasisFunction.h
/usr/include/dolfin/fem/DirichletBC.h
/usr/include/dolfin/fem/DiscreteOperators.h
/usr/include/dolfin/fem/DofMap.h
/usr/include/dolfin/fem/DofMapBuilder.h
/usr/include/dolfin/fem/Equation.h
/usr/include/dolfin/fem/FiniteElement.h
/usr/include/dolfin/fem/Form.h
/usr/include/dolfin/fem/GenericDofMap.h
/usr/include/dolfin/fem/LinearTimeDependentProblem.h
/usr/include/dolfin/fem/LinearVariationalProblem.h
/usr/include/dolfin/fem/LinearVariationalSolver.h
/usr/include/dolfin/fem/LocalAssembler.h
/usr/include/dolfin/fem/LocalSolver.h
/usr/include/dolfin/fem/MultiMeshAssembler.h
/usr/include/dolfin/fem/MultiMeshDirichletBC.h
/usr/include/dolfin/fem/MultiMeshDofMap.h
/usr/include/dolfin/fem/MultiMeshForm.h
/usr/include/dolfin/fem/NonlinearVariationalProblem.h
/usr/include/dolfin/fem/NonlinearVariationalSolver.h
/usr/include/dolfin/fem/PETScDMCollection.h
/usr/include/dolfin/fem/PointSource.h
/usr/include/dolfin/fem/SparsityPatternBuilder.h
/usr/include/dolfin/fem/SystemAssembler.h
/usr/include/dolfin/fem/UFC.h
/usr/include/dolfin/fem/assemble.h
/usr/include/dolfin/fem/assemble_local.h
/usr/include/dolfin/fem/dolfin_fem.h
/usr/include/dolfin/fem/fem_utils.h
/usr/include/dolfin/fem/solve.h