The category also gets other passes from Microsoft: A desktop browser with a Metro version circumvents the Windows Store, and when installed on the Windows 8 classic desktop, simultaneously installs the Metro version.
The biggest caveat for a Windows 8 browser is that only the default browser can run in the Metro UI. During setup, Windows 8 assigns Internet Explorer 10 (IE10) as the default browser. However, users can change the default.
The Nightly build of Firefox can be downloaded from Mozilla's website. To use Metro Firefox, of course, users must install the Nightly on a PC running Windows 8 or on a tablet, such as Microsoft's Surface Pro, powered by the OS.
Firefox cannot be installed on a Windows RT device like Microsoft's Surface RT tablet.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, or subscribe to Gregg's RSS feed . His email address is firstname.lastname@example.org.
Read more about Internet in Computerworld's Internet Topic Center.