The results from endpoints are not what's been documented.
{ {url}}/v3/merchants/{ {mId}}/orders/
does not produce the result listed on your documentation where line item information is included in this one call.
It seems unnecessary to have to call for each order to get the items. Such as...
{ {url}}/v3/merchants/{ {mId}}/orders/{ {orderId}/line_items
Additionally, Categories missing the item id's associated with them per documentation.
Did I miss something?