The Firefox nightly builds that will form the basis of the April 75th release of Firefox 7 have updated the look of the address bar. The most notable change displaying the https:// protocol and the "www" subdomain in the drop-down link block displayed during typing in the address bar (for example, https://opennet.ru and https://www.opennet.ru that differ in content will become indistinguishable). The http:// protocol will continue to show up in the results unchanged. The display of the URL in the address bar will not change either.
Source: opennet.ru