They offer a taste of Android 4.2 Jelly Bean on these older devices
Owners of HTC Desire Z and G2 smartphones now have the possibility to download and install CyanogenMod 10.1 builds on their devices, to see how well they would fare when running Android 4.2.One thing that users should take into consideration, however, is the fact that these are test builds, and that not all features of the platform will work as they might be expected to.
The releases come from the Andromadus team and are based on CM10.1, with a few tweaks packed inside.
As explained in this forum thread on XDA-Developers, these are development builds, which are expected to become more stable as fixes and enhancements are packed inside them.
However, users can already give them a try, though they will do so at their own risk. They will be the only ones held responsible should anything happen with the device.