UA Strings (User Agent Strings) have been, for a long time now, leaking information that certain handsets or Operating System versions are live and in use somewhere in the public domain and according to the latest leak by myce.com it would seem that the Nexus 7 and the Nexus 4 have been spotted running Google’s upcoming 4.3 build.
The versions found were JWR66D and JWR53F which can be broken down to work out what they are.
- ‘J’ tells us that they are Jellybean builds from the second quarter of this year
- ‘W’ is the Android branch that it’s being built from
- ‘R’ and the final number is x-th day in the quarter, in this case the 66th and 53rd.
- The final character remarks the build of the day, the D is the fourth build, the F is the sixth build of that day.
You can find more details on these releases here (or at least bugs relating to them)