rem: assertMIMEStuff(MIME_URI(this.mimeType), "fileExtensions", aExtensionString); 
add: assertMIMEStuff(MIME_URI(this.mimeType), "fileExtensions", aExtensionString.toLowerCase()); 
context:   addExtension: function (aExtensionString)  {    assertMIMEStuff(MIME_URI(this.mimeType), "fileExtensions", aExtensionString);  },
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/3590fb475dd5b57b4d0a31b64e31afecb2dfec1a/overrideHandler.js/clean/suite/common/pref/overrideHandler.js