Rooting a phone lets you take more control over the software running on it, from loading apps that dig deeper into the settings of Android to running completely new operating systems altogether (such as the popular CyanogenMod).
Unlocking and rooting comes with certain extra security risks and most people steer clear because it's not particularly easy to do. In the case of the Pixel and the Pixel XL, it should only take a few minutes with the right tools.
I am root
Have a look at the "root only" apps on the Android apps section of the Google Play Store to see what's possible with rooting: you can tweak battery and CPU performance, perform full phone backups, better control the file system and more.
Most users won't ever need or want to unlock or root their phones but it's something advanced users and developers always look for, and another reason for those particular groups of people to go all in with Google's new pair of devices.
The phones officially go on sale on 20 October: you can pick up the Pixel from $649/£599/AU$1,079 and the Pixel XL from $769/£719/AU$1,269 direct from Google. Stay tuned for our full reviews of both.
Our first look at the Google Pixel phone:
Get daily insight, inspiration and deals in your inbox
Get the hottest deals available in your inbox plus news, reviews, opinion, analysis and more from the TechRadar team.
Dave is a freelance tech journalist who has been writing about gadgets, apps and the web for more than two decades. Based out of Stockport, England, on TechRadar you'll find him covering news, features and reviews, particularly for phones, tablets and wearables. Working to ensure our breaking news coverage is the best in the business over weekends, David also has bylines at Gizmodo, T3, PopSci and a few other places besides, as well as being many years editing the likes of PC Explorer and The Hardware Handbook.