The primary purpose of the Maps4Mac app is to render and search OpenStreetMap data in a SpatiaLite or PostGIS database.
Despite this detail though, Maps4Mac supports and can render any Mapnik XML file.
Loading gpx and kml files, as well as GPS tracking using GPSd are supported but there is no routing yet.
Note:To make Maps4Mac work you have to also add osm2spatialite to your Application folder.
osm2spatialite is a Python script that converts an OSM xml or pbf file into a SpatiaLite database with approximately the same format as an osm2pgsql database.