/usr/include/simgear/scene/material/ is in libsimgear-dev 3.0.0-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/simgear/scene/material/Effect.hxx
/usr/include/simgear/scene/material/EffectBuilder.hxx
/usr/include/simgear/scene/material/EffectCullVisitor.hxx
/usr/include/simgear/scene/material/EffectGeode.hxx
/usr/include/simgear/scene/material/Pass.hxx
/usr/include/simgear/scene/material/Technique.hxx
/usr/include/simgear/scene/material/TextureBuilder.hxx
/usr/include/simgear/scene/material/mat.hxx
/usr/include/simgear/scene/material/matlib.hxx
/usr/include/simgear/scene/material/matmodel.hxx
/usr/include/simgear/scene/material/mipmap.hxx
/usr/include/simgear/scene/material/parseBlendFunc.hxx