Sony opened AOSP software code for the Sony Xperia Z last month, and now the Xperia Tablet Z has been added to the program as well. This will be the first tablet to receive the AOSP port from Sony. The source code will be available through GitHub, usable after the bootloader on the tablet is unlocked. Keep in mind, this software is not intended for everyday use and several apps and services will not be functional.
You can see a Jelly Bean walkthrough of AOSP on the Tablet Z in action below.
Source: Sony Blog