/usr/include/synfig-1.0/synfig/rendering/common/ is in libsynfig-dev 1.2.1-0ubuntu4.
This file is owned by root:root, with mode 0o755.
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/usr/include/synfig-1.0/synfig/rendering/common/optimizer/
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizerblendassociative.h
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizerblendblend.h
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizerblendcomposite.h
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizerblendseparate.h
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizerblendsplit.h
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizerblendzero.h
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizercalcbounds.h
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizerlinear.h
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizerlist.h
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizerpixelprocessorsplit.h
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizersplit.h
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizersurface.h
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizersurfaceconvert.h
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizersurfacecreate.h
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizersurfacedestroy.h
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizersurfaceresample.h
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizertransformation.h
/usr/include/synfig-1.0/synfig/rendering/common/optimizer/optimizertransformationaffine.h
/usr/include/synfig-1.0/synfig/rendering/common/surfacememoryreadwrapper.h
/usr/include/synfig-1.0/synfig/rendering/common/task/
/usr/include/synfig-1.0/synfig/rendering/common/task/taskblend.h
/usr/include/synfig-1.0/synfig/rendering/common/task/taskblur.h
/usr/include/synfig-1.0/synfig/rendering/common/task/taskcallback.h
/usr/include/synfig-1.0/synfig/rendering/common/task/taskcomposite.h
/usr/include/synfig-1.0/synfig/rendering/common/task/taskcontour.h
/usr/include/synfig-1.0/synfig/rendering/common/task/tasklayer.h
/usr/include/synfig-1.0/synfig/rendering/common/task/tasklist.h
/usr/include/synfig-1.0/synfig/rendering/common/task/taskmesh.h
/usr/include/synfig-1.0/synfig/rendering/common/task/taskpixelcolormatrix.h
/usr/include/synfig-1.0/synfig/rendering/common/task/taskpixelgamma.h
/usr/include/synfig-1.0/synfig/rendering/common/task/taskpixelprocessor.h
/usr/include/synfig-1.0/synfig/rendering/common/task/tasksolid.h
/usr/include/synfig-1.0/synfig/rendering/common/task/tasksplittable.h
/usr/include/synfig-1.0/synfig/rendering/common/task/tasksurface.h
/usr/include/synfig-1.0/synfig/rendering/common/task/tasksurfaceconvert.h
/usr/include/synfig-1.0/synfig/rendering/common/task/tasksurfacecreate.h
/usr/include/synfig-1.0/synfig/rendering/common/task/tasksurfacedestroy.h
/usr/include/synfig-1.0/synfig/rendering/common/task/tasksurfaceempty.h
/usr/include/synfig-1.0/synfig/rendering/common/task/tasksurfaceresample.h
/usr/include/synfig-1.0/synfig/rendering/common/task/tasktransformableaffine.h
/usr/include/synfig-1.0/synfig/rendering/common/task/tasktransformation.h
/usr/include/synfig-1.0/synfig/rendering/common/task/tasktransformationpass.h