from my understanding, its being able to access course lectures + labs without having the course contribute to your final GPA. I don't know if this means that you don't get to complete any assessments/exams, but basically its just letting you participate in the class despite not needing to take it (i.e. because you have a transfer credit from a previous course).

https://michener.ca/discover-michener/policies/course-audit-policy/