This object reflects the specialized knowledge required to repair an EE device. Example are a service manual and service instructions targeted to a certified repairer. The manufacturer or an authorized representative controls the repairer certification process. The professional knowledge on a specific product might increase over time, but in general this information will stay with the walls of the repair company (unless published by the manufacterer of course). A repairer might write something on a forum, but then he or she is doing that informally (again, in general).