Firefox 23 has made it to the Aurora channel and, while it may not be rich on new features, there are a couple of interesting additions and changes. For one, Mozilla is continuing with the mixed content blocking experiment, the feature is now turned on by default.The idea is to prevent pages served via encrypted connections to load resources via unencrypted HTTP. You can read more about this here.
It's easier to change search preferences, now, it's possible to do it straight from the search box. What's more, users can now change the preferences for awesomebar and the context menu search from the same place.
Mozilla has also started cleaning up the preferences dialog. The decision was made after it became clear that many options that have been around for a decade or more don't make any sense today and, what's more, they may actually make it possible for users to break the browser.
Finally, perhaps the biggest change of all, symbolically at least, is remove of support for the <blink> element, a plague from a bygone era. As the name suggests, blink adds a blinking effect to text.
Blink was never a standard element, but it was supported by several browsers. In the web's early days, people went crazy with it and used it a lot more than they should have, which is never.
Google even named its new rendering engine for Chrome Blink. That's supposed to mean that the Blink engine will never implement useless, non-standard and annoying features like Blink.
This is becoming a naming tradition at Google, the name Chrome itself comes from browser "chrome," i.e. the UI. One of Google's big goals with Chrome initially was to minimize the UI, the chrome.