One of the biggest features promised for Microsoft's new Edge browser was support for extensions written in HTML and JavaScript. Google developed an API for such extensions for Chrome, and it is being substantially adopted by Firefox. Microsoft said that it, too, would adopt this API for Edge, but extensions didn't make the cut in the November Update.

Since the November Update, Microsoft has released a series of Insider Preview builds that so far didn't actually change a great deal that was visible. But the latest build, version 14291, changes all that, as it includes the first preview of the extension support in Edge. Microsoft has three extensions thus far: two it developed itself (one to perform automatic translation of foreign language pages, another to enable mouse gestures), and a ported version of the popular Reddit Enhancement Suite (RES).

Right now, installing extensions is rather clunky—when this feature is released to end users, extensions will be included in the Windows Store and subject to some amount of vetting and oversight, but that's not plumbed in yet. Once installed, however, the extensions just seem to... work.

I use RES in Chrome, and from an initial poke around, RES in Edge does all the same things for me in the same way—because it's the same extension. Never-ending Reddit mode, inline expansion of images and videos, tagged users, all working in a Microsoft browser.

Early indications are that, at least for simple extensions, little needs to be done to convert a Chrome extension into one compatible with Edge (or Firefox).

Extension support is a big step forward in making Edge usable on a day-to-day basis. Another couple of changes in the new build further improve this. First is support for pinned tabs—tabs that shrink to a small icon in the tab bar and get recreated whenever the browser is reopened. Second, the address bar now has a "paste and go" option for navigating to URLs on the clipboard.

Elsewhere in the operating system, the Maps app has been given a big update, giving it a look and feel that seems a bit closer to that of the Bing Maps Preview. Multiple searches are available as "tabs" along the top of the screen, each one controlling an information panel on the left. Multiple searches can also be overlaid simultaneously, allowing transport directions, for example, to be mixed with searches for landmarks or addresses.

The Maps app has also ditched its awful hamburger menu. This is particularly important on mobile; build 14291 is available for (some) phones, too, and instead of a hamburger menu in the top left of the screen—inaccessible in one-handed operation—major navigation elements are now placed in an app bar along the bottom of the screen. This is a very welcome improvement.

The layout improvements extend to directions, too, with clearer indications of when to get off a bus, and a cleaner screen layout during turn-by-turn navigation. Cortana, or at least her voice, is now also used to read out turn-by-turn directions if she's enabled.

The new Insider Preview build also contains improvements for Japanese text entry using touchscreens and styluses, a revised Alarms & Clock app, and some modifications to the feedback system used for reporting bugs. As ever with preview builds, there are various known issues to be aware of that Microsoft enumerates on its blog. Most notable is an incompatibility with the Surface Pro 3, Surface Pro 4, and Surface Book that has existed for a few builds and still causes hangs on those devices.

I'd be hesitant to use it on a daily driver PC, though the new Maps app and Edge features make this release much more compelling than previous ones. The desirability of the new builds should only continue; we'd expect to see new features revealed at Microsoft's Build developer conference in a couple of weeks.