We use the job description attached to the scheduled job:
The SBMJOB command has INLLIBL as a parameter:
Command: SBMJOB CMD(call pgm(mylib/myprog))
INLLIBL(*JOBD) – or whatever you want
The Add Job Schedule Entry command has JOBD and USER parameters. The JOBD parameter defaults to the user and the USER defaults to the user adding the job schedule entry.