Master Table drop internally/automatically after the successful completion of Job(export/import)
I don't think this has ever been published - a lot of it you can work out yourself by looking at the data. Is there something particular you want to extract from the table?
The master table is dropped after a successful job. It is also a table that could change from version to version so don't expect it's definition to be the same.
What specifically are you looking for that you think is in the master table?