Leaflet.BlurredLocation https://github.com/publiclab/leaflet-blurred-location - A Leaflet-based HTML interface for selecting a "blurred" or low-resolution location, to preserve privacy.

H3 is similar and cool, but this builds a similar nested grid concept around latitude/longitude, which can map to existing coordinate systems and database storage.

Also note that population density affects how effective a given precision "blur" is for an area; we're also hoping to develop a web service or library to roughly return population density for any given region of the globe.