Extracting Dataflow and Dataset fields from PBIX

Hi Team,

We are using Layout file from Reports pbix to extract reports, pages and visuals. But we are not able to extract dataset and dataflow information from layout is there any other file like DataModel which contains the dataset fields and attributes information?

Also not able to view contents of Datamodel file extracted from PBIX

Can you please help in understanding how we can get 

Dataset fields,

Dataflow fields,

Mapping between a Report attribute & a Dataset field or attribute.