App X could be Microsoft Money, QuickBooks, Sage, KMyMoney, Gnucash, Grisbi and others
Source: mail list: ledger.smb.user (Chris Travers and others)
With unknown programs you need to to find out:
1) How much data can you get out?
2) What database system does it use on the back-end?
3) If you cant export data, are there other means (i.e. custom ODBC
drivers, cvs export) that can access the info?
If you can get that information, you are about 50% of the way there.