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|boundary = postal_code|
|A postal code boundary|
|Used on these elements|
|Status: De facto|
|Tools for this tag|
On the relation:
type=boundary boundary=postal_code postal_code=*
On member ways making up the relation†:
† When a way is being shared as an administrative boundary relation (boundary=administrative), and a postal code boundary relation, tag that member way with boundary=administrative. Both boundary types are implied.
This kind of postal mapping is widely used at least in Germany and Belgium.