New mail waveform
You're referring to the new wave-like design of the Gmail notification icon!
Google recently updated the Gmail notification icon to a more modern and sleek design, which resembles a wave. The new icon is a departure from the traditional red envelope design that Gmail has used for many years.
The new wave-like design is meant to evoke a sense of movement and fluidity, and is intended to be more visually appealing and attention-grabbing. The icon is also designed to be more versatile, and can be used across different devices and platforms.
Here's a comparison of the old and new Gmail notification icons:
Old icon:
New icon:
What do you think of the new design? Do you like the updated look, or do you miss the classic red envelope?