/usr/share/libanalitza/plots/3Ds.plots is in analitza-common 4:15.12.3-0ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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plane1 := (x, y, z)->(x+y+z)-1 plane2 := (x, y, z)->(x+y+z)-5