@mat926
Battery Saver is a setting that kicks in when you’re batter percentage is below a specified level. When in battery saver mode, the device will attempt to lower power consumption, including limiting background tasks, throttling the CPU, lowering the screen brightness, adjusting the theme to dark mode, among other things.
System Default is available in Android API 10+. It means, make the theme the same as the system theme (i.e., either light or dark).
