As a Dataverse installation admin or user, I'd like to know which and how many repositories are based in a location

When markers on the current Dataverse installations map are too close together, the overlapping can make it look like there's only one marker:

It looks like there are five markers in Brazil, but there are six. We don't see and can't click on the sixth until we zoom in:

The administrator of a Dataverse installation in Brazil thought the installation wasn't on the map because its marker was hidden behind another marker. This is probably already the case in areas with more markers, like western Europe.

Hidden markers will make it harder for people to find installations in locations with lots of markers. And as more markers are added and hidden, the map will become less of an indication of the growing number of Dataverse installations.

One solution for this using the current map are animated marker clusters. Leaflet has a customizable plugin at https://github.com/Leaflet/Leaflet.markercluster and links to an example at https://leaflet.github.io/Leaflet.markercluster/example/marker-clustering-realworld.388.html.

Other solutions might involve using a list or table of installations that people can navigate to find installations in an area or find a particular installation.

The issue does not name files or tests. Start by locating the current Dataverse installations map implementation and its marker behavior, then compare Leaflet.markercluster with a navigable installations list or table. Done means users can identify and access all installations in locations where markers overlap.