This script is currently in BASH and would be better served as python:
https://github.com/small-hack/kaartmaker/blob/main/download_geojson.sh

Then we can avoid shipping with expensive large geojson files.

The geojson files should be stored in $XDG_CACHE_HOME or $XDG_DATA_HOME (info about XDG spec). If those variables aren't set, try using the OS's default application storage location e.g. ~/.local/share/kaarmaker/ or ~/.cache/kaarmaker/.