What is the property of matrix $S$ to be near-identity matrix for $M$, e.g. $SM$ is close to $M$?

Question

I have a matrix $S$:

tensor([[ 0.3600,  0.2100,  0.4300, -0.0000],
        [ 0.2100,  0.9300, -0.1400,  0.0000],
        [ 0.4300, -0.1400,  0.7100, -0.0000],
        [ 0.0000, -0.0000, -0.0000,  1.0000]])

and matrix $M$:

tensor([[0.3658, 0.3338, 0.1566, 0.1438],
        [0.2850, 0.3646, 0.1580, 0.1924],
        [0.3979, 0.2923, 0.1555, 0.1544],
        [0.3177, 0.3192, 0.2076, 0.1556]])

It turns out product $SM$ is very close to $M$, even though $S$ is far from identity matrix. What is the name of this property of matrices $S$ with respect to $M$?

To be clear, matrix $S$ was produced by multiplying matrix $Q$ by it's pseudoinverse $Q^+$

Q
tensor([[0.3333, 0.3333, 0.3333],
        [0.0000, 1.0000, 0.0000],
        [0.5000, 0.0000, 0.5000],
        [0.0000, 0.0000, 1.0000]])

Q+
tensor([[ 0.8570, -0.2860,  1.4290, -1.0000],
        [ 0.2140,  0.9290, -0.1430,  0.0000],
        [ 0.0000, -0.0000, -0.0000,  1.0000]])