With XCOM for z/OS 11.6 there is a new JES-file being introduced as additional file in the Job Output of every XCOM transfer Job and for the XCOM Server. It is named XCOMINIT and lists all parameters from the Configuration member and from the PARM-Field of the EXEC-Statement. Parameters of the SYSIN Statement are listed in the XCOMLOG. If your Job has multiple XCOMJOB steps there will be one XCOMINIT file for each of them in the joblog.
If you want to remove that file you can do this by specifying this DD-card:
//XCOMINIT DD DUMMY
However, this is not recommended because the list of parameters can help in debugging if an XCOM transfer fails for whatever reason.