GS1-128: the details
Each piece of data is preceded by an application identifier in parentheses that says what it is: (01) the product code or GTIN, (10) the lot, (15) the best-before date, (17) the expiration date and (00) the SSCC, the serial number that uniquely identifies each pallet. A scanner that understands those identifiers can interpret any label, whichever supplier it comes from.
It’s what makes it possible to receive goods without typing and to follow a lot along the chain. Big retail requires it on the pallet label, usually together with an EDI ship notice announcing which SSCCs are on the truck. The most common failure isn’t printing but data: a correct label with the wrong lot.