This is a simple style that adds a small white border to all markers, including playerheads.
By default, BlueMap just has a dropshadow behind each marker icon.
| Original | Marker Borders |
|---|---|
 |
 |
 |
 |
Thanks to a community member @NorskNoobing for providing this cool feature!
Download or copy the BlueMapMarkerBorders.css file to your webapp, and register it.
(guide)