A new, even lower-power mode may be coming to Android phones in the future. XDA Developers' Mishaal Rahman spotted a commit made to the AOSP (Android's source code), which adds a new "ultra-low power state" to future versions of Android, and circumstantial details indicate it might be destined for an upcoming Pixel phone.
Speculation: "Ultra low power" mode may be a feature of the Pixel 5. This commit was just submitted to AOSP by a "System Power Engineer" at Google.https://t.co/KEDUdTPIi8
It's a generic implementation without framework hooks for now, but that'll likely change soon.
— Mishaal Rahman (@MishaalRahman) February 10, 2020
As noted, the feature will likely save additional power over and above the battery saver mode first introduced with Android 5.0 Lollipop. The existing mode works by reducing how frequently apps refresh their content, disabling always-on voice commands, disabling background operations, increasing the interval between standby device wakes, and forcing a dark theme, among other changes.
This new mode will likely impose additional restrictions on top of that, but we aren't sure what they are. Limiting things like which apps you can launch may be included.
Although nothing about the commit itself draws a connection to Google's Pixels, Rahman notes that the engineer that submitted the commit has only ever previously worked on Pixel-related code. Although it might not be tied to any one anticipated device, there's a very good chance based on that history that this is destined for a future Pixel.