hello,
I never saw a symantec document which listed these jobs, you may ask to your symantec support contact if it is available.
By default incident deletion happens at midnight everyday. This could be changed in "System/Incident data/incident deletion" page of DLP UI.
You may have some DLP users who scheduled some incident report during this period. It is not possible to have a full view on them using DLP UI.
Data Insight could also have some scheduled task if you used it.
If you want to investigate deeper, DLP is using QUARTZ scheduler to manage scheduled task so information should be available in QUARTZ tables in DLP database (IP_QRTZ_job_details, IP_QRTZ_triggers, IP_QRTZ_simple_triggers, IP_QRTZ_cron_triggers, IP_QRTZ_calendars,...) and DLP table ReportEmailSchedule.
Regards.