World boundaries: Natural Earth 1:110m, public domain. https://www.naturalearthdata.com/about/terms-of-use/
Country coordinates/names: mledoze/countries, ODbL-1.0. https://github.com/mledoze/countries
City coordinates: GeoNames cities15000, CC BY 4.0. https://www.geonames.org/export/
Downloaded 2026-09-22. City matches are exact normalized city+country and unambiguous only. All positions are approximate geographic centers, not street addresses. Country-level fallback is explicit.