It seems that Pixel phones now have a new option regarding how the device alerts users to incoming calls. A small feature on some devices gives people the ability to vibrate the phone and then ring gradually when receiving a call. 9to5Google reports that last week, it started appearing on Pixel 4, but older Pixels understand it too.
Until now, the feature would’ve been enabled on the pixels, pixels 2, 3, and 3a, as well as the corresponding XL variant of each device. The feature is available in Settings> Sound> Vibrator for calls. Once the switch is ON, the function will use the vibration motor as soon as a call arrives, but will slowly introduce the buzzer until the volume reaches its higher volume, as the call remains unanswered.
The vibration lasts about 5 seconds before the buzzer starts ringing. It will not exceed the defined volume level when it increases. It goes slowly from the silence setting to the previous setting in a few seconds. I imagine this could be useful in meetings because it gives you a chance to silence the phone before it makes noise without the phone is in vibrate mode only.