The developer unlocked a 90Hz display refresh rate on the Google Pixel 6a
The Google Pixel 6a features a 6.1-inch OLED display with a 60Hz refresh rate and no 90Hz mode, but there's a technique to enable it. TheLunarixus, a Twitter user, has developed a modification that enables the Pixel 6a's 90Hz mode; they're also working on making it easier for any Pixel 6a owner to activate the higher refresh rate using a custom ROM. It's not clear, if the display panel really supports 90Hz, or whether it's merely overclocking it to reach the higher refresh rate.
The mod is the result of many people in the Android community noticing that the Pixel 6a's Samsung display has similarities to the larger Pixel 6 display, and interest was piqued. Google enables 90Hz on its 6.4-inch Pixel 6 screen, but the two screens are not identical.
The mod is now quite extensive. To enable 90Hz mode on the Pixel 6a, you must first turn on debugging mode and OEM unlocking in the settings (which you might not be able to do if your phone is locked to a carrier), then unlock the bootloader, manually flash an Android 13 beta with some checks disabled, and finally install a modified vendor_boot image.
If none of that made sense, or you've never heard of XDA Developers, it's probably best to put off installing a custom ROM. The end result of all these modifications is the option to switch on Smooth Display and force the maximum refresh rate in the developer settings to 90Hz.
Many others in the Android community have also tried this mod and verified its legality. After installing the modification, Mishaal Rahman observed a green tint on his phone, and we've noticed it as well (although some people don't have the problem).
There are also some concerns about the Pixel 6a's display long term health. Developer Kuba Wojciechowski predicts that Samsung may not rate the Pixel 6a's display at up to 90Hz, and that this is almost certainly just overclocking. The Lunarixus claims we won't know for sure until the modification is tested on more than 100 phones.