The news came from Android Police, giving some evidence of Google planning to make a next version of Jelly Bean dubbed as, Android 4.3 Jelly Bean MR2. According to AP, they have found visits in there server logs that originated from Nexus 4 & Nexus 7 devices running Android 4.3 with build number JWR23B. The first character of the build shows that it is still being called as Jelly Bean.
The IP addresses of these visits were found to be associated with Google, cementing the fact that these visits might not be fakes.
We already posted about plans of Google to delay the launch of next Android Version "Android 5.0 Key Lime Pie", so we can expect Google to launch another version of JB at Google I/O 2013. The News is still a Rumor & we can't assure the Confirmation.
The build version JWR23B was also spotted on Chromium Project Site, pertaining to some errors, which also indicates that the build is real.
Source - Android Police
To be updated...