Google Pixel And Nexus Gets March 2017 Android Security Update
Google has released new factory images for most supported Pixel and Nexus devices, which has the March 2017 Android security update. The update is available for Pixel, Pixel XL, Nexus 6P, Nexus 5X, Pixel C, Nexus 9 (+LTE), and Nexus 6.
You can download the security update on Google's developer sites here and here. Please note that these images available on the site are not for novice, but for experienced users and OEM. You can either risk flashing these updates manually or wait for the OTA update to hit your device.
Builds for the Pixels are NOF27B for all variants except devices on Rogers, which should use build NOF27C. The Nexus Player appears to be left out of the March updates at this point.
You can find the accompanying security bulletin here, which as usual lists a significant number of security threats that have now been eliminated.