/usr/share/gwyddion/glmaterials/Polished-Bronze 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
0.25 0.148 0.06475 1.0
0.4 0.2368 0.1036 1.0
0.774597 0.458561 0.200621 1.0
0.0 0.0 0.0 1.0
0.6
|