From MozillaZine Knowledge Base
Firefox 2.0 incorporates the Google Safe Browsing extension in its own Phishing Protection feature to detect and warn users of phishy web sites. This preference, along with browser.safebrowsing.remoteLookups, determines whether or not the Safe Browsing functionality is active.
Possible values and their effects
Compare visited URLs against a blacklist or submit URLs to a third party to determine whether a site is legitimate. (Default)
Disable Safe Browsing.
A checkbox labeled “Block reported web forgeries” is located under Tools → Options → Security.
In SeaMonkey 2.18 and later, this checkbox is located in the Edit → Preferences → Privacy & Security main tab.
First checked in
Has an effect in