Hey @janklima ,
Happy to help you out with this.
As you’ve already discovered the checkout id field is not an exposed field when performing order queries in GraphQL. If you don’t mind me asking, what is the checkout id field being used for? Knowing what it’s being used for could help in suggestion of a possible alternative, and also help in any communication I have with internal teams.
Look forward to hearing back from you.
Regards,
John