Microsoft yesterday stuck a knife in Internet Explorer (IE) when it announced that the 23-year-old browser would appear as a "mode" within Edge in its new "full-Chromium" incarnation.

While the Redmond company did not publish a death notice for IE or even admit to browser-cide, as sure as Law & Order's churning cast yanked criminals off streets, IE's days as a stand-alone browser are numbered.

"The new Internet Explorer mode ... seamlessly render[s] legacy IE-only content in high fidelity inside of Microsoft Edge, without the need to open a separate browser or for the user to change any settings manually," Kyle Pflug, a senior program manager lead who heads the developer ecosystem team, asserted in a post to a company blog. "Microsoft Edge uses your existing Enterprise Mode Site List to identify sites which require IE rendering and simply switches to Internet Explorer mode behind the scenes."

Enterprise Mode is a Windows 10 feature that allows enterprise IT administrators to define which websites and web apps are opened in IE; currently, those sites and apps launch within the separate Internet Explorer 11 (IE11) bundled with Windows 10.

Even though Microsoft built Windows 10 on the concept of multiple browsers - IE11 and Enterprise Mode for legacy sites and apps, Edge for all the rest - Pflug now derided the idea. "We hear from our customers that most enterprises rely on a multiple-browser solution today, and we hear from our customers and partners that this experience is disjointed and confusing," he said, implying IE is one of those browsers. (According to analytics data Net Applications, Chrome is the most likely partner in such scenarios.)

In hindsight, IE's demotion should have been foreseen months ago when Microsoft program manager Chris Jackson belittled the application by calling it "a compatibility solution" and telling users that the more they used it, the further behind they'd fall.

Pflug did not describe how the new IE11 mode will work within Edge when the latter wraps up its based-on-Chromium transformation. But no matter how Microsoft does it, its process won't be a first. Similar solutions have been around for years.

One of the best known is IE Tab, a Chrome extension available since 2009 that displays pages using IE inside Google's browser. It does almost exactly what Pflug said the IE mode would do inside the revamped Edge. Another is Browsium's Catalyst, a tool that acts as an IT traffic cop, directing some sites and apps to open in one browser, Firefox or Chrome, say, and others in IE. And Google offers something like Catalyst - dubbed "Legacy Browser Support" (LBS) - to enterprise customers for handling required-IE pages and apps.

Just last month with the release of Chrome 74, Google moved LBS from browser-external to browser-internal. The add-on that was once required no longer needs to be installed to use LBS. Once configured, usually by enterprise IT administrators, LBS automatically opens IE11 when links clicked within Chrome lead to websites, web services or web apps requiring Microsoft's browser, or more likely, IE's ActiveX controls or Java - neither of which Google's browser supports.

By tucking IE11 into Edge, Microsoft will be able to dispense with standalone IE and keep its promise to support the legacy browser for an unspecified future. Microsoft has linked IE11's support to that of Windows 10, saying that the former will be maintained with security updates as long as the latter is also in support. "Internet Explorer 11 will continue receiving security updates and technical support for the lifecycle of the version of Windows on which it is installed," the company stated in a FAQ on the browser.

Earlier this year, Computerworld laid out why it was unlikely that Microsoft would support IE indefinitely. One thing left unconsidered, however, was the browser-in-a-browser angle Microsoft decided to take. Even so, if Microsoft can add an IE mode to Edge, it can just as easily remove it when the old browser's no long useful to customers or too much of a burden in Redmond to justify continued support.

In the meantime, IE integration can only help Edge's battle for some browser share. If Microsoft, as Computerworld expects, stops supporting stand-alone IE11 when full-Chromium Edge (with IE inside) reaches the Stable release channel, commercial users who require IE will take the path of least resistance and adopt Edge on Windows 10, the still-in-support Windows 8.1 and those Windows 7 PCs on the post-retirement paid support dole.