Returns metadata for each attachment on a received email: the `attachment_id`, declared filename, MIME type, and size. The same manifest is embedded in [Get a received email](/docs/api/reference/get-inbound-message); fetch an individual attachment's bytes with [Get a received email's attachment](/docs/api/reference/get-inbound-message-attachment). Metadata for every attachment on the message. Empty when the message had no attachments. Attachment ID, stable within the received message. Filename from the attachment's Content-Disposition, or null when the sender did not name the part. MIME type parsed from the attachment part, or null when absent. Size of the attachment in bytes.