It isn't. The table names are found inside the TDS's XML document, which is stored as a BLOB inside the postgres database. So, you'd need to find correct TDS record in the database, use it to point to the correct BLOB, and then use Postgres's lo_export or some other function to "export" the BLOB to a file which you would then parse.
Tamas Foldi wrote something called "TableauFS" which allows you to connect to PostgreSQL as a file system and then browse it's content like you would folders on your OS. Pretty cool and might be useful to you - of course it's unsupported and only works on Linux and OSX.