The BlackBerry Z10 just got one of its first relatively usable OS 10.2 beta leaks in the form of OS 10.2.0.820. This new leak is available for the BlackBerry Z10 STL100-2/3/4 models except for the STL100-1. This is definitely not as clear cut as the OS 10.1 leaks and has quite a few caveats which I highly recommend reading and considering before downloading. Adam Szucs did a good job of writing up the FAQ with the release on CrackBerry forums and I highly recommend reading it all. In short it does have Jelly Bean, notifications work, phone calls work, restores are iffy, battery usage is high, and it may lock up sometimes. On the other hand a few on the BR team have been running it successfully this weekend so its not an unusable release.
Check out the download here and proceed at your own RISK!