mapnik-inspect <datasource>
mapnik-inspect <stylesheet>
mapnik-inspect <projection>
mapnik-inspect <zipfile>

datasource: .shp|.json|.geojson|.osm|.kml|.sqlite|.gml|.vrt|.csv
stylesheet: .xml (requires node-carto)
projection: .prj (requires node-srs)
zipfile: .zip (requires node-zipfile)