World country geometry derived from datasets/geo-countries:
https://github.com/datasets/geo-countries
Source: Natural Earth, https://www.naturalearthdata.com/downloads/10m-cultural-vectors/
License: Open Data Commons Public Domain Dedication and License v1.0 (ODC-PDDL-1.0)
https://opendatacommons.org/licenses/pddl/1-0/
Local modifications: geometry simplification, coordinate rounding, ISO alpha-2 feature names, Antarctica omitted.

SignalTally report map: additional Douglas-Peucker simplification at 0.13 degrees; precomputed SVG paths in an equirectangular view. No ECharts runtime required.