https://thenextweb.com/insider/2020/02/21/android-11-lets-you-assign-shortcuts-to-a-double-tap-on-the-back-of-your-phone/

When I moved from a Pixel 3 to 4, I found myself missing the fingerprint sensor much more than expected. Not because of the fingerprint reader itself – Google’s Face ID works surprisingly well – but because I used the fingerprint reader to pull down the notification shade all the time. It turns out Google is working on an alternative in Android 11.

As spotted by XDA Developers, Android 11 includes a hidden double-tap-on-the-back-of-your-phone gesture for Pixel devices. Codenamed ‘columbus’ in an inside joke for Zombieland fans, you can assign this double-tap to a number of different actions, including: