Script Triggers
There are many script triggers in the database.
Media: In order for the Export IPTC Data script to work, the field Media::ExportCaption needs to be filled out. That is done via a script trigger that is connected to the Caption, and MediaLink::SerialSubject and MediaLink::Note fields in all of the Media layouts. So whenever someone edits one of those fields, when they leave the field the ExportCaption field is filled out. So when the Export IPTC Data script is run, the ExportCaption field is already populated.
auditTrail: See the auditTrail page for more on the general use. For any field to be recorded in the audit trail, the necessary script trigger has to be added to every occurrence of that field on every layout. Otherwise the changes won't get recorded. The necessary triggers are OnObjectEnter run CaptureAuditOnEnter and OnObjectSave run StoreAuditOnSave. Enable in only browse mode.