To get user information of the performer of an activity.
Prefix
performer
Attributes
#performer.activityDefId.id#
#performer.activityDefId.username#
#performer.activityDefId.firstName#
#performer.activityDefId.lastName#
#performer.activityDefId.email#
#performer.activityDefId.active#
#performer.activityDefId.timeZone#
To get activityDefId (activity definition ID), mouseover the activity name in the Activity Mapping tab (Workflow Management Console); there will be an overlay showing the ID.