Windows Phone 8 running on the Nokia Lumia 920 has been allegedly jailbroken, or so hackers poandsou and Silen Tech claim. The team showed a photo and video of the handset with three columns of tiles rather than the usual two; a feature, normally reserved for 6-inch devices like the Lumia 1520, that can only be enabled by modifying the system registry.
The idea with this jailbreak is that a third-party store could be included on devices letting people install non-approved apps, and there's a possibility for registry editing, device customization and the modification of low-level OS settings. In many ways the jailbreak would be similar to those available for iOS, like the recent one we saw for iOS 7.
At this stage there are no details on how the Windows Phone 8 jailbreak was accomplished. Users might potentially be able to install the jailbreak through running some software on a PC, but there's a chance something more complex might be required, like a JTAG with hardware access.
As WPCentral points out, the hackers responsible for this jailbreak have yet to fully detail the methods they've used, so it's entirely possible that the whole thing is bogus (especially as photos can be easily faked). It has been promised by the team that the jailbreak will be released to the public when completed, but that could be some time away.
This jailbreak wouldn't be the first to unlock Windows Phones. Chevron WP7 was a tool available during the Windows Phone 7 years that allowed people to install homebrew apps on their handsets, and Microsoft even assisted in its development. However modifying devices wasn't as popular in the Windows Phone community as it is for Android, so it remained a very niche tool.