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use firebirdsql-full.jar as JDBC driver in DBVisualizer.
URL: jdbc:firebirdsql:embedded:<filename.fdb>
e.g.
jdbc:firebirdsql:embedded:d:\FEWS\testfews\EFAS\localDataStore\local.fdb
username: xxxx (ask anyone from FEWS support or a FEWS-expert)
password: xxxxyyy (ask anyone from FEWS support or a FEWS-expert)
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