vaadin.addon.leaflet pointfield Which epsg or srid?

Regarding the vaadin.addon.leaflet pointfield

Which epsg or srid does pointfield use?
I figured if I supply the Geometry in EPSG:4326
than the locations are approximately in the right area, but not 100% correct.

I searched with google but could not find anything about what pointfield uses internally.

Leaflet offers three projections out of the box
https://leafletjs.com/reference-1.3.0.html#projection