Is there a supported API field (such as tab metadata, recipientId association, or document-level metadata) that links a signer attachment document to a specific recipient?

In DocuSign, when using Signer Attachment tabs for multiple recipients in a single envelope, what is the recommended way to programmatically identify and download each signer’s uploaded attachment separately after envelope completion?

Currently, I can retrieve all documents using the Envelopes API, but I cannot reliably map each uploaded attachment back to the specific recipient who uploaded it.

Is there a supported API field (such as tab metadata, recipientId association, or document-level metadata) that links a signer attachment document to a specific recipient?