https://wccftech.com/android-10-source-code-90hz-refresh-rate-pixel-4/

With Google’s latest and greatest software update officially available, a little digging in the Android 10 source code reveals something more interesting about the Pixel 4. Currently, the only mainstream flagship (not counting gaming devices) with a 90Hz refresh is the OnePlus 7 Pro, and after reading this news, you guys are probably wondering why more manufacturers aren’t making the extra effort to incorporate high refresh rate displays on their devices. If the latest leak turns out to be true, Google will only be the second manufacturer to roll out a mainstream flagship with a 90Hz panel.

XDA Developers’ Mishaal Rahman spent some time searching the Android 10 source code to find something noteworthy, and sure enough, here it is. While examining changes made to Android’s SurfaceFlinger, he spotted several commits related to screen refresh rates. One of them shows the implementation of an overlay to reveal when the device is running a refresh rate of 60Hz or 90Hz. Since the Pixel 3a and Pixel 3a XL have shipped with 60Hz refresh rates, it can only mean the upcoming Pixel 4 will tout a 90Hz refresh rate.