Firefox: Enable/Disable HTTP Referrer

You can enable or disable the referrer from being reported to web sites that you visit with this Firefox tweak.
1. Type about:config in the address bar and press Enter.
2. Find the entry that says Network.http.sendRefererHeader and double-click on it.
3. Set the entry to one of the following:

• 0 – Disable referrer.
  
• 1 – Send the Referer header when clicking on a link, and set document.referrer for the following page.
• 2 – Send the Referer header when clicking on a link or loading an image.