Google rolled out the 4.4.4 update to devices earlier this year, with the 2013 Nexus 7 seeing the OTA in mid June. Here we are over three months later and Google has finally posted the full factory images and binaries for the LTE version of the N7. It's about time, guys.
Factory images differ from an OTA update in that they contain the entire software build for the device. Even if you've flashed 20 ROMs and tweaked your kernel all to hell, flashing the system image gets you back to 100% stock. There are sometimes licensing-related delays in getting these files up on the website, especially with devices packing cellular radios, but this is a much longer wait than usual.
The Nexus 7 is still technically the current Nexus tablet, despite being more than a year old at this point. Maybe work on this device has slowed down as the release of the long-rumored Volantis/Nexus 9 got closer. Either way, download at your convenience at the links below.