It's just under a month after the brand new Pixel devices came out, so naturally developers and custom ROM makers have been hard at work building their wares for the new phones. Included in this is TWRP, the most popular custom recovery for Android (RIP ClockworkMod).
TWRP for the Pixel and Pixel XL is still in alpha format, meaning it is still buggy and should not be used if you're not aware of what you're doing. Specifically, restoring data is not working correctly, because of the new file-based encryption (which enables Direct Boot) that the Pixels employ. TWRP's lead developer Ethan Yonker says in a Google+ post that, "If a restore doesn't work correctly, it can trigger an automatic wipe of your data," which doesn't sound like fun at all. There are also issues surrounding decrypting backup data, which Yonker says are due to a timing issue that has not been fixed yet.
So, if you have a Pixel and want to install TWRP, remember it's not stable and will most likely break something. The recovery images for both the Pixel and Pixel XL can be downloaded at the TWRP site. You can also find the instructions there too, which you should read if you don't want to permanently break your device or do other damage.
- +Ethan Yonker (Dees Troy)