add:  var strBundleService = Components.classes["@mozilla.org/intl/stringbundle;1"].getService(); strBundleService = strBundleService.QueryInterface(Components.interfaces.nsIStringBundleService);  var extbundle = strBundleService.createBundle("chrome: var themesFilter = extbundle.GetStringFromName("themesFilter"); fp.appendFilter(themesFilter, "*.jar"); 
context: function installSkin(){  // 1) Prompt the user for the location of the theme to install. Eventually we'll support web locations too.  var fp = Components.classes["@mozilla.org/filepicker;1"].createInstance(nsIFilePicker);  fp.init(window, document.getElementById("installSkin").getAttribute("filepickertitle"), nsIFilePicker.modeOpen);  fp.appendFilters(nsIFilePicker.filterAll);  var ret = fp.show();  if (ret == nsIFilePicker.returnOK)   {    var ioService =    Components.classes['@mozilla.org/network/io-service;1'].getService(nsIIOService);    var fileProtocolHandler =    ioService.getProtocolHandler("file").QueryInterface(nsIFileProtocolHandler);    var url = fileProtocolHandler.newFileURI(fp.file).QueryInterface(nsIURL);    InstallTrigger.installChrome(InstallTrigger.SKIN, url.spec, decodeURIComponent(url.fileBaseName));  }}
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/a5230d88e295ac220907a330f2bec497f6a28b53/pref-themes.js/clean/mail/components/prefwindow/content/pref-themes.js