Alert Notification Subject Variables for PPDM

I've got a PPDM Server (v19.18) which sends various emails alerts to our Storage Team, but we have to open or preview each individual email to know what the alert is about.  For now, I've created multiple Alert Notifications for each important Category, but that can still be rather vague at times.  I'd like to include more granular information into the Subject line of an alert, so I am hoping that there are Variables that I can include.  Can someone give me any insight into that?  If there's a document somewhere that details them, I'd appreciate it if someone could direct me.

Thank you in advance.

Matthew