When you generate a COBOL program for a CICS® environment, the startTransactionID build descriptor option indicates the transaction ID used to start that program. The default is the first four characters of the program alias or, in the absence of an alias, the first four characters of the program name.
This option has no affect at run time; instead, the value of startTransactionID identifies the transaction ID in a CICS definition that is generated when the cicsEntries build descriptor option is set to a value other than NONE.