Import is a two stage process.
1) Genbridge imports the data from the source database in a text data stream.
2) This data stream is processed by TMG (using the appropriate app) and the data is added to a new TMG project (or appended to an existing project).
I don't know if the data stream is directed to a temporary text file or if it is processed in memory. If a text file is created, it will be located in the TMG session folder located in the system temp folder. You would need to copy the file from the temp folder while the session is active.
I have debugging tools to create the intermediate GenBridge text file containing the data stream. The procedure for doing this is fairly obscure. You might ask Support for the GenBridge development kit.
The GenBridge text file just shows you what GenBridge has processed. It does not tell you how the data is going to be saved in the project that will be created by the import.
The only reason that I use the GenBridge debugging tools is to identify errors in the GenBridge process. Seeing what and how data is imported is best done by comparing the data in the source database to the data in the TMG project resulting from the import.
Import is an imperfect process. Only data that fits the TMG data model will be imported.