/usr/share/gwyddion/glmaterials/Polished-Gold is in gwyddion-common 2.38-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 | Gwyddion resource GwyGLMaterial
0.24725 0.2245 0.0645 1.0
0.34615 0.3143 0.0903 1.0
0.797357 0.723991 0.208006 1.0
0.0 0.0 0.0 1.0
0.65
|