I have used the .bax file to pull markup data from files and visualize in Power BI. Currently this is a manual process by saving a file from a Session locally and exporting the .bax file. We are looking into ways of using the Bluebeam APIs to extract markup data from these Session files. Currently I believe there are export options for json and csv (possibly others), but I don't believe there is an option to export the .bax file.