What stands behind your question? You want to modify that behavior?

On average, if to follow standard logic, then probably PXGenericInqGrph graph, because it is repsonsible for all generic inquiries.

I’m not sure if Dashboards behind the curtains use some graph so far.

@Yuriy Zaletskyy 

No, it is irrelevant to GI question. I was going to do some monitoring work on users login activities. So I need to know what is the first graph when user logs in triggered by the platform.

In that case, I would suggest to analyze page users of Acumatica with help of dnSpy. It has tracking of who signed in into the system and when regardless of graph. Potentially you just can see what kind of information it writes in DB and use it.