NODE_MATRIX_DEFAULT is slightly vauge warning.

NODE_MATRIX_DEFAULT is vauge because it doesn't convey what it actually means. In the code, the issue is added when a node's matrix is an identity matrix. I understand this could be argued as an alternate way of saying this but last I checked identity matrix is the more common term.

Start by locating NODE_MATRIX_DEFAULT in the validator source and trace where the warning is added for a node whose matrix is an identity matrix. The work is done when the warning name clearly uses the identity-matrix terminology without changing the validation behavior.

Written by the indexing model from the issue text.