/usr/include/pigment-0.3/pgm/ is in libpigment0.3-dev 0.3.17-1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/pigment-0.3/pgm/gtk/
/usr/include/pigment-0.3/pgm/gtk/pgmgtk.h
/usr/include/pigment-0.3/pgm/imaging/
/usr/include/pigment-0.3/pgm/imaging/pgmimaging.h
/usr/include/pigment-0.3/pgm/pgm.h
/usr/include/pigment-0.3/pgm/pgmcanvas.h
/usr/include/pigment-0.3/pgm/pgmcommon.h
/usr/include/pigment-0.3/pgm/pgmdrawable.h
/usr/include/pigment-0.3/pgm/pgmenumtypes.h
/usr/include/pigment-0.3/pgm/pgmevents.h
/usr/include/pigment-0.3/pgm/pgmimage.h
/usr/include/pigment-0.3/pgm/pgmimagesink.h
/usr/include/pigment-0.3/pgm/pgmkeysyms.h
/usr/include/pigment-0.3/pgm/pgmlinearalgebra.h
/usr/include/pigment-0.3/pgm/pgmmarshal.h
/usr/include/pigment-0.3/pgm/pgmmodule.h
/usr/include/pigment-0.3/pgm/pgmplugin.h
/usr/include/pigment-0.3/pgm/pgmtext.h
/usr/include/pigment-0.3/pgm/pgmversion.h
/usr/include/pigment-0.3/pgm/pgmviewport.h
/usr/include/pigment-0.3/pgm/pgmviewportfactory.h