How to determine if a learner enrolled in the offering or it was assigned as voluntary assignment

Summary:

How to determine if a learner enrolled in the offering or it was assigned as voluntary assignment

Content (required):

Is there a way to tell if an offering is assigned as a voluntary learning item or if the learner enrolled in the course/offering themselves? In none of the searches it is differentiating such assignments.

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):