Firefox about:config Entry - ""

Understanding the about:config Entry in Firefox

firefox about:config browser startup
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This article is only intended for users running the Mozilla Firefox Web browser on Linux, Mac OS X, macOS Sierra, and Windows operating systems.

about:config Entries is one of hundreds of Firefox configuration options, or Preferences, accessed by entering about:config in the browser's address bar.

Preference Details

Category: browser
Preference Name:
Default Status: default
Type: integer
Default Value: 1


The Preference in Firefox's about:config interface allows the user to specify which Web page(s) is opened when their browser is initially launched.

How to Use

The value of can be set to one of four integers: 0, 1, 2, or 3. When this Preference is set to 0, a blank page (about:blank) is opened upon launch. The default value, which is set to 1, causes Firefox to open whatever page(s) is set as the browser's homepage. When the value is set to 2, the Web page that the user last visited is opened. Finally, when the value is set to 3, the user's previous browsing session is restored.

To modify the value of, follow these steps:

  • Open your Firefox browser.
  • Type about:config in your browser's address (or URL) bar.
  • Hit Enter.
  • A list of Firefox Preferences should now be displayed. Locate the entry with a Preference Name value of
  • Double click on this entry. A dialog box should appear prompting you to enter an integer value.
  • Enter the desired value (0, 1, 2, or 3) and click on the OK button.