Why do some orders have two confirmation numbers? + how can they be searched for?

[noahtren]

It appears that orders placed through Meta apps (FB and IG) have two confirmation numbers via the API for one of our customers. They are just comma separated, so for example a response might be:

>>> order.confirmation_number
'7073064942134395,4420256445714170'

*This is a made up pair of confirmation numbers

Two questions:

The first question is out of curiosity, it doesn't seem to be documented anywhere and the Meta apps tend to provide just the first confirmation number in emails and messaging. So why are there two?

Secondly, is it possible though either the REST Admin API or the GraphQL Admin API to make a request to retrieve an order given just one of these confirmation numbers? In the example above, we might only have access to '7073064942134395' which does uniquely identify that order, but searching for { confirmation_number: '7073064942134395'} returns no results since it isn't a perfect match.

Thanks so much!