This site describes solve-engine as it is on main: 2.43.0, which npm does not have yet. npm installs 2.40.0, so a page may show an answer that version does not give yet.
GEO_PACKAGE
const GEO_PACKAGE: IEnginePackage;Defined in: packages/engine/src/packages/geo/GeoPackage.ts:207
Geo: places on the globe by their coordinates, the distance between two of them, the direction from one to the other, and angles written as a map writes them.
A coordinate is a latitude (how far north or south of the equator) and a
longitude (how far east or west of Greenwich), both in degrees. The distance
is the great-circle distance, the shortest path over the Earth’s surface,
worked on a sphere of the mean radius (see GeoMath.ts for why a sphere);
the bearing is the compass heading at the start of that path.
The boundary: places are typed as coordinates, or held in a variable. There is
no built-in list of cities and nothing reaches the network, so distance from London to Tokyo needs London and Tokyo defined first. The distance is as
the crow flies, not by road, and ignores height above the ground.