/usr/share/gwyddion/glmaterials/Bright-White is in gwyddion-common 2.44-1.
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
0.2 0.2 0.2
0.8 0.8 0.8
0.5 0.5 0.5
0.0 0.0 0.0 1.0
.35
|