CiviCRM User Reference is an optional module for the _staff modules that move the Author field up to the top of forms. This includes cm_project_staff, cm_show_staff, and reservations_staff.

When CiviCRM User Reference is enabled, these fields will lookup Drupal users by the first and/or last name in CiviCRM instead of the Drupal username. This allows users use an odd nickname instead of something more conforming.