question about Regression​Partitione​dModel

I have a question about the RegressionPartitionedModel documentation. I understand this is an evaluation for error (cross-validation error). I would like to know where the actual model is. Since this is under Regression Partitioned Model, I was wondering where the Regression model is actually seen?

The example shown is:

cvtree = fitrtree(X,MPG,'crossval','on');

Can I know where the MPG is estimate is, as a function of the X (both horsepower and weight)?

Thanks