What is the meaning of each distinct potential value in the "source" column in the Data Access Platform, Catalog Namespace, orders table?

[dacarter]

In the Instructure Data Access Platform, when querying the Namespace: Catalog, the orders table, there is a column called "source".  The distinct values from my full data pull are:

"bulk_purchase", "live_event", "enrollment", "shopping_cart", and "invitation_code"

I understand "bulk_purchase" and "shopping_cart", but I'm not sure the other 3.
My guess for "enrollment" is that it covers enrollments in courses that are ordinarily paid through Catalog, but which are manually enrolled from Canvas because payment was arranged by other means, but I still don't understand how that generates an order record. The "live_event" and "invitation_code" values don't mean anything from my frame of reference.  Any clues? This isn't the only place in the DAP where the documentation is not as informative as it could be, or perhaps I'm missing out on something where this is well-documented.

[hechla]

This is purely speculation on my part, but the invitation_code might be attached to the bulk_purchase. When someone makes a bulk purchase they can then invite others to use those seats. I'd have to assume there's a distinct code attached to the invitation so Catalog knows to enroll the user with that invite from the bulk purchase. 

Other than that, info about the DAP is beyond my skill or knowledge level.