The Android 4.4.2 Factory Images have been posted for the Nexus 5, Nexus 7, Nexus 7 (2013) and Nexus 10 models. Having the latest Factory Image available will allow those with the covered devices to experiment with customizing their device without fear that they might accidentally turn it into a brick or paperweight permanently.
Google does not want you to use these files for any reason other than what they were intended to be used for. And once you have successfully flashed your device with the proper Factory Image, Google reminds you to lock your bootloader for safety reasons. And please watch out for flying monkeys.