Are you talking about the actual data? The actual data files is stored as .TDE files in the Data Engine folder but they do not have "friendly" names and are not persistent - the Data Engine process will create and reap them as it needs. Files are, by default, in this location: C:\ProgramData\Tableau\Tableau Server\data\tabsvc\dataengine\extract
Does that answer your question?
Thanks Nathan! I located the .TDE files but I am looking for the source they use to refresh. I think they are stored separately on Tableau server. If I publish an extract called DatabaseA that makes a call to a database "Select Column1, Column2, Column3 FROM DatabaseA" I want to see where that definition is stored. I believe it is just an XML file stored somewhere.
Ah! Yes - the connection information is not stored in the .TDE files (otherwise they would be called .TDSX). I believe you are correct that it is stored as XML data, I'm not sure where it's located though.