Nice try man, but I will tell you there is no shit in powericon() because it is just calling other functions to calculate the parameters for use under the synchronous machine mask, and you cant find these functions at all. Actually, all standard parameters will be converted to fundemental parameters for simulink simulation, but there is no explicit way in Simulink help to calculate, say, the fundemental parameters, using the standard parameters. Kundur's book 'power system stability and control' example 4.1 mentioned the conversion between funemental and standard parameters. I have tried it myself in Simulink and we can see the two synchronous machines using the two kinds of paramters in this book differ a little, but the conversion only stands for round stators. Kundur's book didnt mention the conversion of salient pole machines.
If you are not talking about the conversion between fundemental and standard paramters, there is one simulink example helping you understand the calculation of the parameters. "Interfacing Simulink Models with Simscape Electrical Specialized Power Systems" (power_SLmodeling) has a customed current-source-modeled synchronous machine with identical characteristics as synchronous machine models in the library. The parameters of the current source block is in power_SLmodeling_data and you can open it because it is a .m file. The composition of the parameters under the mask, like SM.R, SM.Linv, SM.RLinv, are all in this file. However the model is just a fundemental salient pole machine, so there is no parameter conversion, and there are some parameters missing compared with round stator machine ( Rkq2 and Lkq2 for salient pole doesnt have this 1 branch )