Postcode data — source and licence
==================================

The files DE.json, AT.json and CH.json in this directory are derived from
GeoNames, the free geographical database:

    https://www.geonames.org/
    https://download.geonames.org/export/zip/

GeoNames data is licensed under the Creative Commons Attribution 4.0 licence:

    https://creativecommons.org/licenses/by/4.0/

That licence permits use and redistribution, including commercially, and is
compatible with this plugin's GPLv2-or-later licence. It requires attribution,
which is given here and in the plugin's readme.txt.

What was changed
----------------
The original GeoNames export is a tab-separated table with one row per
postcode/place pair. It has been reduced to the two fields this checkout needs
(place name and administrative region), grouped by postcode, and stored as
JSON so a lookup is a single array access.

How it is used
--------------
The files are read from disk when a customer types a postcode, and only the
matching city names are returned. No request leaves the shop, and no address a
customer enters is transmitted anywhere.
