There has been a lot of news which we covered earlier about the Android 4.4 KitKat by Google and the Nexus 5 being spotted with Android 4.4 KitKat. A reputed and known source has mentioned about the Android 4.4 KitKat build which is found. The bug-tracker of the Chrome browser reveals Android Kitkat or Key Lime Pie build such as KRS74B running on a Nexus 4 and Nexus 10.
About two days ago, a Google developer reported a bug while running Chrome on a Nexus 10 with Android version: ‘ mantaray-userdebug KLP KRS74D‘. You could click on the reported link to view and have a better view of what it is , in case you are a hard-core Android developer. The build number KRS74D likely means that it is Kitkat or Key Lime Pie builds from the Primary Development Branch which is made in the third quarter 2013.