In the world of mainstream Web browsers, Microsoft stands alone. Apple's Safari browser is a closed source shell wrapped around an open source rendering engine, WebKit. Google's Chrome browser is a closed source fork of an open source shell wrapped around an open source rendering engine, Blink. Opera, too, puts its own shell around the Blink engine. Mozilla's Firefox is entirely open source.

But Internet Explorer is closed from end to end. While the same kind of logical separation as is found in Safari and Chrome exists—the Internet Explorer shell is separate from the Trident rendering engine—both components are entirely proprietary.

This puts Internet Explorer at a disadvantage. While the Web community has a multitude of different priorities and agendas, and the different participants frequently do not see eye-to-eye, it nonetheless has a consistent attitude of openness. Web standards are developed in public, and except for Internet Explorer, Web browsers (or at least, the most important parts of browsers, their rendering engines) are likewise developed in public.

This enables open discussion of and experimentation with new features. The public bug trackers that go hand in hand with the open development lets interested third parties monitor the development of features they care about and even provide detailed feedback before the code has been finalized.

And while it's a minority interest, the availability of source enables the community to find bugs and even contribute fixes.

It's time for Microsoft to fit in with the rest of the browser industry and open up Trident.

One might argue that this argument could be made of any software, and that Microsoft should by this logic open source everything. But I think that the browser is special. The community that exists around Web standards does not exist in the same way around, say, desktop software development, or file system drivers, or user interfaces. Development in the open is integral to the Web in an almost unique way.

One could also argue that there is some precedent with Microsoft's decision to open source large parts of .NET. In open sourcing .NET, Microsoft has been able to solicit feedback from the community—including bug fixes—and improved the ability of .NET developers to detect and diagnose problems both in their own code and in the .NET code.

The community targeting the Web has development expertise, and developing Trident in the open would allow them to bring this expertise to bear on the browser's engine, just as it is doing so for .NET.

Opening Trident's development might have further advantages down the line. It's hard to imagine a world where Internet Explorer for OS X is ever a major concern again, but equally, it's not impossible that one day some industrious developers might make Trident work on that platform.

In so doing, they'd make it easier for designers and developers using OS X to test their projects in Trident, without having to use Windows virtual machines or other such heavyweight approaches. It's not going to revolutionize anything, but it could make Trident a little more relevant to a community that otherwise cares little for it.

Although Microsoft has endeavored to be more open about how it's developing its browser, and which features it is prioritizing, that development nonetheless takes place in private. Developing in the open, with a public bug tracker, source code repositories, and public discussion of the browser's future direction is the next logical step.

Speculation is currently rife that with Windows 10, Microsoft will in some ways put Internet Explorer out to pasture. The browser is believed to have a new name, a new shell, new extension capabilities, and a new, streamlined version of Trident, one that has much of its support for legacy Web pages removed.

This represents an ideal time for the company to make this kind of move. With a cleaned up engine representing a new baseline for future development and a range of new developer-oriented extension capabilities, the time is right for Microsoft to stop being the odd one out and open up Trident. Put it on GitHub, track its bugs and development branches in public, make it a peer to WebKit, Blink, and Gecko.

Listing image by Aurich Lawson