L.GeoJSON layer group is just a Feature Group with extra methods specific for vector layers.
It provides a convenient conversion from a GeoJSON data object into a layer group made of Leaflet vector shapes converted from the GeoJSON data. In particular, a
LineString is converted into an
L.GeoJSON group is in the end just a container for your Polylines.
Therefore you can directly add and remove child layers like with a normal group (
removeLayer methods). You can add and remove child Polylines, whether built automatically at construction from the GeoJSON object, or added later on through
addLayer (or even through
If you want to shorten / extend a Polyline (through
addLatLng methods), of course you can also do it, provided that you get the direct reference to your Polyline.