why is MLpnp's Jacobian so complicated?

[lturing]

hello, thank you very much. I have a question about the Jacobian matrix in MLPnp. Does the Jacobian matrix come from the partial derivative of the eq(11) in the origin paper? If so, I'd like to know why it is so complicated. For example, is $\frac{\partial error}{\partial t_1}=r1$ or s1 ?