The Readout Error in Qiskit is described here: https://qiskit.org/documentation/stubs/qiskit.providers.aer.noise.ReadoutError.html
Although it is easy to obtain such an error for 1-qubit for IBMs available QPUs it's very unclear as to what is a reasonable 2-qubit readout error or n-qubit readout error and how to construct it.
Where can one find information for modelling such errors?