From OpenStreetMap Wiki
|for the Hungarian national VAT identification number|
|Used on these elements|
|Tools for this tag|
ref:vatin:hu is a tag to add the national version of theon Wikipedia (usually the number of the operator found on the receipt you get when you pay something). The usual syntax is 12345678-1-23. If the given business has requested an EU VAT identification as well, the given EU identifier will match the first 8 digits of the national identifier. Note that not all businesses are required to hold an EU VAT identification, but they are required to hold a valid national VAT identification.
- ref:vatin:hu=12345678-1-23 for a business in Hungary
You can attach this key to every business, usually it refers to the operator of the place. Some also: