You can use the Quick Map facility within the Repository 3270 interface to find the table associated to a map.
1. From the Repository command line issue the command QMAP xxx (where xxx is your Repository map).
ex.
QMAP 204
2. Within Quick Map select DETAILS.MAP from the pulldown menu and the underlying DB2 table will be presented on this screen in the ENTITY TABLE NAME field.
An alternative method is to query the repository control tables directly.
For example,
SELECT ENT_TBL_NAME FROM repowner.DBX_IO_MAP_DESC WHERE MAP_ID = 204;