The first is a full-featured proxy API, which will, for example, allow users to set different proxy servers for normal browsing and Incognito mode. Proxy auto-config scripts are also supported by the API.

The second -- Web Navigation Extension -- is a bit more expansive. This API will allow devs to build everything from more powerful safe browsing extensions -- like Traffic Light -- to data analysis and reporting extensions.

Both APIs are currently experimental, so you'll need to enable them on the about:flags page to try out any relevant extensions. Apart from a proxy example built by Google and shipped with the Chromium source, we're not aware of any examples just yet, however. We'll let you know when we spot any slick, new extensions which do surface.

After originally reporting on the introduction of WebKit2 back in April 2010, it looks like it will finally be rolled out with OS X Lion, in a new version of the Safari Web browser.

WebKit2, rather than being a whole new rendering engine, is a layer around WebKit that adds more stability, security and speed -- not entirely unlike the Google Chrome sandbox, which is also strapped onto a version of WebKit. The most exciting feature of WebKit2 is that it splits the browser UI and the rendered content into separate processes. It's possible that each tab will have its own process, too, like Chrome.

This is the first solid news of a Safari update since the minor revisions of desktop and iOS versions back in November. It also represents a major change for the browser, so we wouldn't be surprised if it is Safari 6, rather than 5, that ships with OS X Lion.

We're also hoping to see some benchmarks from the Lion version of Safari. Split processes is definitely a huge step forward, but its JavaScript performance is the thing that really needs to improve. Presumably WebKit2 isn't the only change that Apple plans to make to a new version of Safari, so here's hoping!

If there's one single thing that truly sets Chrome apart from its herd of rivals, it's the Omnibar. Chrome users already know and love this feature, but Google's just made it possible for developers to create extensions that will push it even farther ahead of the competition by providing an API for it. Now, there are already huge numbers of extensions available for Chrome -- many of which we here at Download Squad couldn't live without -- but none of them have thus far been able to make full use of the Omnibar.

As an example of how the API can be used, take a look at Switch to Tab, shown above. It allows users who leave ridiculous amounts of tabs open to use the Omnibar to search them all for the specific tab they need to find. It only shows up to 5 results right now, but the concept is pretty decent just the same -- and there's no telling what kind of goodies that devs will come up with now that they can treat a browser's address bar like a command line.

In a strong, head-held-high missive, Adobe has detailed a new initiative to bring Flash local storage clearing to Web browser UIs. The new API, NPAPI ClearSiteData will let Firefox and Chrome users clear Flash's Local Shared Objects, or 'Flash cookies,' in the same way that you currently clear cookies and temporary Internet files.

LSOs are very commonly used throughout the Web, but unlike conventional cookies they're a little harder to delete. A lot of websites use them to track you across the Web, but they're also used by sites like YouTube to store your video preferences.

In a move that is surely an effort to keep pace with Firefox's helter-skelter development of Jetpack, Chrome Beta now has a context menu API!

There's also a bunch of other new APIs, the most exciting being the Omnibox API. Imagine Chrome's built-in search engines (type 'Amazon', then a space, and then a book name -- it searches Amazon!), but with extension access. Type the name of an extension into the Omnibox, and then any further input is redirected to the extension. Actually, having said this is an exciting addition, I'm really not sure what an extension would do with it... Perhaps something Ubiquity-esque?

The new Infobar API might be of interest, too. You know that blue bar that appears when Chrome asks you whether you want a page to be translated? Well, extensions can now pop those up for you. I can see security and privacy extensions like LastPass making use of them, or an extension that alerts you when a page you're visiting has an 'official Chrome extension' (you know, instead of that awful JavaScript hack...).

Oh, and if you make an extension (featuring the new APIs? It's not clear), let Google know and they might send you a free Chrome hoodie! Hooray.