If you want to be sure about the usage of a job, there are currently three ways.
The Where-used list (in the main or context menu) can be executed directly in the eBiss user interface. Jobs may only be referenced in Automations or Workflows.
Alternatively, a system dump can be searched with a suitable tool(like for example: GrepWin or Notepad++) for the job name. If more than one1) hit is found, it must be assumed that the job is needed2).
The obsolete manual way is to search through all jobs and automations.
Note: In multi-node systems with public jobs3) each node must of course be dumped and evaluated individually.