The course registrations are transmitted to Moodle by the central UHH-Login service of the University of Hamburg.
Moodle stores course registrations in a hidden profile field. They are not visible to students or teachers. Each number refers to a course in the course management system STiNE and enables students to be automatically enrolled in courses, as long as the lecturers have configured the course accordingly.
The course registrations are updated each time you log in. It is not possible to change them manually in Moodle.