10.3 (Panther): http://swscan.apple.com/scanningpoints/scanningpointX.xml
10.4 (Tiger): http://swscan.apple.com/content/catalogs/index-1.sucatalog
10.5 (Leopard): http://swscan.apple.com/content/catalogs/others/index-leopard.merged-1.sucatalog
10.6 (Snow Leopard): http://swscan.apple.com/content/catalogs/others/index-leopard-snowleopard.merged-1.sucatalog
10.7 (Lion): http://swscan.apple.com/content/catalogs/others/index-lion-snowleopard-leopard.merged-1.sucatalog
10.8 (Mountain Lion): http://swscan.apple.com/content/catalogs/others/index-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog
10.9 (Mavericks): http://swscan.apple.com/content/catalogs/others/index-10.9-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog
10.9 (Mavericks incl. seeds): http://swscan.apple.com/content/catalogs/others/index-10.9seed-10.9-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog