/usr/share/dolfin/demo/undocumented/dg-advection-diffusion/ is in dolfin-doc 2016.2.0-2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/dolfin/demo/undocumented/dg-advection-diffusion/cpp/
/usr/share/dolfin/demo/undocumented/dg-advection-diffusion/cpp/AdvectionDiffusion.h
/usr/share/dolfin/demo/undocumented/dg-advection-diffusion/cpp/AdvectionDiffusion.ufl
/usr/share/dolfin/demo/undocumented/dg-advection-diffusion/cpp/CMakeLists.txt
/usr/share/dolfin/demo/undocumented/dg-advection-diffusion/cpp/Projection.h
/usr/share/dolfin/demo/undocumented/dg-advection-diffusion/cpp/Projection.ufl
/usr/share/dolfin/demo/undocumented/dg-advection-diffusion/cpp/Velocity.h
/usr/share/dolfin/demo/undocumented/dg-advection-diffusion/cpp/Velocity.ufl
/usr/share/dolfin/demo/undocumented/dg-advection-diffusion/cpp/main.cpp
/usr/share/dolfin/demo/undocumented/dg-advection-diffusion/python/
/usr/share/dolfin/demo/undocumented/dg-advection-diffusion/python/demo_dg-advection-diffusion.py
/usr/share/dolfin/demo/undocumented/dg-advection-diffusion/unitsquare_64_64.xml.gz
/usr/share/dolfin/demo/undocumented/dg-advection-diffusion/unitsquare_64_64_velocity.xml.gz