First, create a disablesafemode directory in distribution/bundles where the Firefox executable is located (you'll probable have to create the distribution and bundles directories as well). Then create a file called chrome.manifest that looks like this:

content disablesafemode content/
override chrome://browser/content/safeMode.xul chrome://disablesafemode/content/safeMode.xul

Then create a subdirectory called content. In that directory, create a file called safeMode.xul that looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet href="chrome://global/skin/"?>
<dialog xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
        id="safeModeDialog"
        buttons=","
        ondialogcancel="closeFirefox();">
  <script type="application/x-javascript;version=1.7">
  <![CDATA[
  function closeFirefox() {
    Components.utils.import("resource://gre/modules/Services.jsm");
    Services.startup.quit(Services.startup.eForceQuit);
  }
  ]]>
  </script>
  <description>
  Safe Mode has been disabled.
  </description>
</dialog>

This will cause a dialog to be shown instead of the safe mode dialog that when the user closes, will simply close Firefox. If you'd prefer to show no dialog at all, change ondialogcancel to onload.

I've tested this a lot, and it is working for me. Please let me know if you have problems.

   var handlerSvc = Components.classes["@mozilla.org/uriloader/handler-service;1"].getService(Components.interfaces.nsIHandlerService)
  // Change "image/tiff" the mime type you want to set the preference for
  var realMIMEInfo = mimeService.getFromTypeAndExtension("image/tiff", "");

  var file = Components.classes["@mozilla.org/file/local;1"].createInstance(Components.interfaces.nsIFile);
  // This should be the path to the .app file on Mac or the EXE on Windows
  file.initWithPath("/Applications/Preview.app");
  var localHandlerApp = Components.classes["@mozilla.org/uriloader/local-handler-app;1"].createInstance(Components.interfaces.nsILocalHandlerApp);
  localHandlerApp.executable = file;
  // The name that will be shown in preferences.
  // Not used on Mac
  localHandlerApp.name = "Preview";
 
  realMIMEInfo.preferredApplicationHandler = localHandlerApp;

  // This says to always use the helper app 
  realMIMEInfo.preferredAction = 2; // useHelperApp
  // This says not to ask
  realMIMEInfo.alwaysAskBeforeHandling = false;

  handlerSvc.store(realMIMEInfo);

You can add this code to your autoconfig file.

• defaults/preferences -> browser/defaults/preferences
• defaults/profile -> browser/defaults/profile
• extensions -> browser/extensions
• searchplugins -> browser/searchplugins

I've also been asked about the file override.ini - this file should now be placed in the browser subdirectory as well.

Remember, Firefox 21 is scheduled to be released tomorrow.

If you really think you have a use case for unpacking the omni.ja[r], let me know and I'll try to prove you wrong.

Now you know...

In addition, for files in the defaults/preference directory, there were issues with JS files only working if the filename started with a letter less than f. That problem appears to not be there anymore either.

So to summarize, you can set extensions.autoDisableScopes via autoconfig (and you should) and it doesn't matter what your JS file in defaults/preferences is named.

In order to support the metro version of Firefox, most of the Firefox code was moved into a subdirectory called browser. This means that all configuration files except the autoconfig now go into the browser subdirectory:

• browser/distribution
• browser/defaults/preferences
• browser/defaults/profile
• browser/extensions
• browser/searchplugins

So just about every blog post I've ever done on this stuff doesn't apply starting with Firefox 21. Also be aware that these changes will be in the ESR 24.

In addition, there is a new feature called Firefox Health Report that is on by default. You can see it by going to about:healthreport. This feature sends data about Firefox to Mozilla. You have two choices here. If you want to be able to see the data, and just not have it sent to Mozilla, set the preference "datareporting.healthreport.uploadEnabled" to false. If you want to turn it off completely, set the preference "datareporting.healthreport.service.enabled" to false.

Being a contributor to Mozilla has allowed me to have some amazing experiences.

• Working with some incredible people in the partner engineering center at Netscape. I couldn't possibly name them all, but a lot of the Mozilla relationships I have now started in that building.
• Leading the team that ported Mozilla to OS/2 as the IBM Web Browser.
• Leading the team that ported Firefox to OS/2.
• Traveling around the world talking to people about OS/2 browsers.
• Getting to meet Sergey Brin in the early days of Google at Technical Advisory Group meetings with Mozilla, IBM, Google, Red Hat and others.
• Taking Blake Ross to meet Sam Palmisano, the CEO of IBM, to talk about Firefox.
• Working with IBM Israel and IBM Egypt to get bidirectional language support (Hebrew and Arabic) into Mozilla.
• Working on Operator and getting microformats support into Firefox
• Creating the CCK and enabling hundreds of enterprises to customize and deploy Firefox.
• Releasing a Firefox version of IE8 Activites before IE8 had it.
• Starting Kaply Consulting after leaving IBM which enabled me to continue to develop and advocate for Firefox.

Thanks, Mozilla, for 15 years. And thanks to all the people who have helped me get here.

I'm releasing this on Friday of this week, so if you have problems, please let me know.

There have been sporadic reports of bookmarks not working and certificates not installing. If that happens to you, I can't debug it without the XPI, so please send that to me if you have the problem.

Rather than go into detail here, the best place to point you is an entry on the Mozilla Wiki - Installer:Command Line Arguments

With this add-on installed, URLs that typically make the URL bar go away behave like normal URLs.