How to get addional information from 3rd party apps for an order?

Hey!

I’m integrating Zakeke to personalize items and use the GraphQL-API to read the order infos.

This is how the generated order looks. Zakeke creates the additional print files which are shown in Shopify. I can use the API to get the information about Quantity etc, but I did not find a way to also read the additional information.
How can I get all available information for a LineItem in an order?