grep -r "new get_string" *

lib/classes/event/course_completed.php: return new get_string('eventcoursecompleted', 'core_completion');
lib/classes/event/course_completion_updated.php: return new get_string('eventcoursecompletionupdated', 'core_completion');
lib/classes/event/course_module_completion_updated.php: return new get_string('eventcoursemodulecompletionupdated', 'core_completion');