Apologies to update an old thread but as I was looking into tuning this alert myself I thought I'd take the time to give an answer for the 2k views still wondering:
Take a look at the alerts search string itself, it's using "datamodel=Change_Analysis.All_Changes", so the "All_Changes" dataset of the "Change_Analysis" datamodel. You can view events from this by using either: | datamodel Change_Analysis All_Changes search
or | from datamodel:Change_Analysis.All_Changes
I ended up tuning out the audittrail and fs_notification sourcetypes from the datamodel as they were generating noise and not needed in my use case.
You can then of course add fields to the datamodel where needed, and include them in the alert search with something along the lines of | tstats summariesonly=false allow_old_summaries=true count as change_count values(All_Changes.src) as "Source" values(All_Changes.Operation) as "Operation" values(All_Changes.dest) as "Destination" from datamodel=Change_Analysis.All_Changes...etc
and lastly (and optionally) tack on a | fields - WhereCIX to the end of the search to make the alert a bit more readable.