Scheduled report emails when executed will send an email to the end-users. Every notification email that the instance creates or receives is recorded in an Email [sys_email] record. You can navigate to a log of these records at System Logs > Emails. Sometimes, we might want to know which scheduled report has sent the email.
You can use the "target" field on the sys_email table to get the information. It stores the sys_ID of the scheduled report which has triggered the email notification.