The Pixel XL is currently receiving the Android 7.1.2 Nougat update globally, but it looks like a few customers received a Googlers-only dogfood build containing next month's security update. Google tests its builds internally ahead of release in a process called dogfooding, which gives Googlers the ability to share feedback and find any bugs before a wider OTA rollout commences.

Pixel XL dogfood build

This time around, regular Pixel XL customers ended up getting the internal-only OTA update. According to screenshots sent to Android Police, the update clearly mentions that it is a "confidential internal only" build meant for Googlers, adding that employees should not "discuss or comment" on the update externally.

The update itself comes in at 62.3MB and features the May 02, 2017 security patch. The build number is incremented to N2G470, and there don't seem to be any user-facing changes in the build. Hopefully, the actual update should be hitting the Pixel and Pixel XL along with Nexus devices by the end of the month.