Worldmap-tracks - what does 'Track Layer' do?

Playing with the worldmap-tracks node (part of node-red-contrib-web-worldmap) and there is a configuration option 'Track Layer' but no explanation (that I can find) of what it does.

Sooo, what do the three options do

  • on marker layer
  • one per marker layer
  • single Track layer

on the worldmap page there is a layer selector - we can either add the tracks to the same layer as the markers are on (so turning it on/off turns off both markers and tracks), a tracks layer that is related to the marker layer so you can just turn off the tracks independently, or all onto a single tracks layer.