Looking at the add-on, we can infer the developer recognized device generated notifications as external alerts and tagged them appropriately. I.e. The device generated an event of note separate from any traffic logging it may be performing.
For example, event type pan_system_alert uses the following search:
sourcetype=pan_system OR sourcetype=pan:system AND log_subtype="url-filtering"
pan_system and pan:system have both been used historically as source types. log_subtype comes from the extract_system transform.
In your screenshot, the event likely indicates the device's URL database was updated. If you're dependent on the device to perform URL filtering, alerting, etc. a configuration change of this type is probably important from a change or configuration management standpoint. An operations team may want to correlate the alert with a change request, for example, and consider the event suspicious if the correct process wasn't followed.