Observers can view the same content as the student they are observing unless the content is unpublished or restricted by locked dates.
Observers can view module content locked by prerequisites or requirements, as module progression is not measured for observers.
Observers can view assignments even if the student they are observing has not completed them unless the assignments are locked.
Each instructor can customize the links in the Course Navigation and limit the number of features that students and observers can see. Observers may or may not see links to certain features.