/usr/share/pyshared/matplotlib/backends/ is in python-matplotlib 1.1.1~rc1+git20120423-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/pyshared/matplotlib/backends/__init__.py
/usr/share/pyshared/matplotlib/backends/backend_agg.py
/usr/share/pyshared/matplotlib/backends/backend_cairo.py
/usr/share/pyshared/matplotlib/backends/backend_cocoaagg.py
/usr/share/pyshared/matplotlib/backends/backend_emf.py
/usr/share/pyshared/matplotlib/backends/backend_fltkagg.py
/usr/share/pyshared/matplotlib/backends/backend_gdk.py
/usr/share/pyshared/matplotlib/backends/backend_gtk.py
/usr/share/pyshared/matplotlib/backends/backend_gtkagg.py
/usr/share/pyshared/matplotlib/backends/backend_gtkcairo.py
/usr/share/pyshared/matplotlib/backends/backend_macosx.py
/usr/share/pyshared/matplotlib/backends/backend_mixed.py
/usr/share/pyshared/matplotlib/backends/backend_pdf.py
/usr/share/pyshared/matplotlib/backends/backend_ps.py
/usr/share/pyshared/matplotlib/backends/backend_qt.py
/usr/share/pyshared/matplotlib/backends/backend_qt4.py
/usr/share/pyshared/matplotlib/backends/backend_qt4agg.py
/usr/share/pyshared/matplotlib/backends/backend_qtagg.py
/usr/share/pyshared/matplotlib/backends/backend_svg.py
/usr/share/pyshared/matplotlib/backends/backend_template.py
/usr/share/pyshared/matplotlib/backends/backend_tkagg.py
/usr/share/pyshared/matplotlib/backends/backend_wx.py
/usr/share/pyshared/matplotlib/backends/backend_wxagg.py
/usr/share/pyshared/matplotlib/backends/qt4_compat.py
/usr/share/pyshared/matplotlib/backends/qt4_editor/
/usr/share/pyshared/matplotlib/backends/qt4_editor/figureoptions.py
/usr/share/pyshared/matplotlib/backends/qt4_editor/formlayout.py
/usr/share/pyshared/matplotlib/backends/tkagg.py
/usr/share/pyshared/matplotlib/backends/windowing.py