For "one ID concepts" or "common supplier/customer concepts" expecially in organisations with fragmented system landscapes it would be beneficial to know where and in which source an existing business partner record is stored.
The idea is, during the First Time Right or Business Partner Look up, when you enter a business partner and this business partner exists already in your legacy data source or legacy data sources it would be beneficial to get the information where the information is stored (e.g. SAP ERP, SAP C4C, ACE, Sales Force etc...)
Information already available in the API response. Data source description could be useful. Both should be displayed in the lookup results in the Apps.