European Commissioner Joaquin Almunia told Reuters that Microsoft's Steve Ballmer is taking the issue "very, very" seriously and that the company is "taking measures" so that other browser makers are not prevented from being part of the new Windows 8 operating system. Apparently, some companies had complained that IE's rivals were blocked from running under Windows 8.
There appears to be no issue of an installation capability, but the more problematic complaint is the notion that Windows does not provide rival browser makers with full access to APIs for the integration in Windows 8. Given Microsoft's direction, it is much more essential to the browser integration that certain features are supported, rather than the issue of being prevented from an installation itself.
It will also be critical for browser makers to support a rich, hardware-accelerated UI of web apps. Microsoft has been fine tuning the acceleration capability of IE since the release of the first preview versions of IE9 in March of 2010.