Class

AutofillType.PostalCodeExtended

Indicates that the associated component can be auto-filled with an extended ZIP/POSTAL code.

Common
PostalCodeExtended,

Indicates that the associated component can be auto-filled with an extended ZIP/POSTAL code.

In forms that split the U.S. ZIP+4 Code with nine digits 99999-9999 into two fields annotate the delivery route code with this hint.