COUNTRY OUTLINES
Geographic data and credits

The downloadable country-outlines.json collection is available under the Open Data Commons Open Database License 1.0. Individual upstream sources retain their original licenses.
https://opendatacommons.org/licenses/odbl/1-0/

Natural Earth
Most boundaries use the public-domain 1:10 million Admin 0 countries from Natural Earth, version 5.1.2.
https://www.naturalearthdata.com/
https://www.naturalearthdata.com/about/terms-of-use/
https://github.com/nvkelso/natural-earth-vector/tree/v5.1.2

geoBoundaries
The following small countries and island groups use gbOpen ADM0 boundaries distributed by geoBoundaries. The source release is pinned to commit 9469f09.
https://www.geoboundaries.org/
https://github.com/wmgeolab/geoBoundaries/tree/9469f09/releaseData/gbOpen

• Kiribati, Liechtenstein, the Marshall Islands, Monaco, Nauru, San Marino, Seychelles, Tonga and Tuvalu. © OpenStreetMap contributors, via Wambacher and geoBoundaries. Open Database License 1.0.
  https://www.openstreetmap.org/copyright

• Singapore. Urban Redevelopment Authority, Singapore, Master Plan 2014 Subzone Boundary (No Sea), via geoBoundaries. gbOpen records the boundary license as Open Database License 1.0.
  https://data.gov.sg/dataset/master-plan-2014-subzone-boundary-no-sea

• Federated States of Micronesia. OCHA Regional Office for the Pacific, Federated States of Micronesia Division of Statistics (2010 Census of Population and Housing), and Secretariat of the Pacific Community Statistics for Development Division, via geoBoundaries. CC BY 3.0 IGO.
  https://data.humdata.org/dataset/fsm-2010-administrative-level-0-2-boundaries
  https://creativecommons.org/licenses/by/3.0/igo/

• Maldives. Sentinel-2 10-Meter Land Use/LandCover, via geoBoundaries. CC BY 4.0. Contains modified Copernicus Sentinel data.
  https://env1.arcgis.com/arcgis/rest/services/Sentinel2_10m_LandCover/ImageServer
  https://creativecommons.org/licenses/by/4.0/

• Malta and Vatican City. geoBoundaries and Wikimedia Commons. Public domain.
  https://commons.wikimedia.org/wiki/File:DistritosMalta.PNG
  https://commons.wikimedia.org/wiki/File:Flag_map_of_Vatican_City.svg

Cartographic adaptations
The quiz uses north-up local projections and simplified coastlines. It omits some distant possessions. Alaska and Hawaii appear as insets. Widely scattered island countries have a main island or island-group detail with a wider inset. Small marks in that inset indicate island positions at a readable size.