Ustrd is the camt.053 free-text remittance carrier at <TxDtls>/<RmtInf>/<Ustrd>. It is the catch-all field where any human-readable note the originator sent ends up: invoice numbers, order ids, comments, even concatenated remittance lines.
iso-compliant regex-extracts candidate references from Ustrd content using a default pattern (/[A-Z]{2,}[-_]?\d{4,}[-_]?\d+/) that catches common shapes like INV-2026-001234, UBS-2026-001, ORD20260603_42. Customers can override the pattern via the ustrdKeyPattern option on the parse request — important for tenants whose invoice references do not match the default shape.
A candidate extracted from Ustrd is always lower confidence than one extracted from StrdCdtrRef or EndToEndId. The matching engine in reconcile.ts re-ranks candidates per carrier and per bank handler before walking them against the expected-payments list.