grid_examples/grid_F0F1F2.py import: projection_matrix ?

I tried to run another example, grid_examples/grid_F0F1F2.py and (just for plotting at the end) it tries to import "projection_matrix", which I don't have and couldn't find through pip. What's that package? Or is it a local file you forgot to commit?

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information