I'm writing to suggest a valuable improvement to the Xero API: the ability to directly identify which invoices are linked to projects.

While I've explored the existing endpoints for both invoices and projects, I haven't found a clear way to establish this relationship through the API data itself.

Currently, it's challenging to determine which invoice line items are assigned to specific projects. This functionality would be highly beneficial for streamlining workflows and gaining deeper insights into project profitability.