Android 12 has a double tap on the back gesture for the Pixel 5, but it isn't active yet - Android

Google likes to throw in some interesting physical gestures for its phones—see the "squeeze" function the older Pixels inherited from HTC, or the short-lived Soli gestures in the Pixel 4. There's another one the company has been brewing for a while, at least on the Pixel 5: double-tapping the back of the phone for some frequently-used actions.

This tool has been present on the Pixel 5 since the first Android 12 Developer Preview, but as of DP2 it still isn't actually available to use.

Android 12 has a double tap on the back gesture for the Pixel 5, but it isn't active yet was written by the awesome team at Android Police.