/usr/share/k3d/lsystem/spiral-tree.ls is in k3d-data 0.8.0.3-3build1.
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 7 | # --- L-System Parser/Mutator --- Lj Lapre ----------------------------------
8
10
80
FFFF[C]>>>>>>>>>[C]>>>>>>>>>[C]>>>>>>>>>[C]
C=F!^+F^+;'[c---C]C
@
|