4.4.0-138.164) is not available, but a newer one is (4.4.0-142.168). We redirected you there.
/usr/share/gwyddion/gradients/Green is in gwyddion-common 2.50-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 | Gwyddion resource GwyGradient
0 0 0 0 1
0.5 0 1 0 1
1 1 1 1 1
|