The Battery Health functionality found within the Settings app has been moved to the Settings Services app (baked into the QPR1 Beta 2). It gives you an estimate of your battery capacity and offers tips on prolonging battery health.
As Mishaal Rahman states, the Settings Services app baked into the QPR1 Beta 2 image is actually older than the latest publicly available one on Google Play/APKMirror, so he had to downgrade the app then install the one from the OS image in order to get this.
Activity name:
com.google.android.settings.intelligence.modules.battery.impl.health.BHSettingsActivity
🔗 Mishaal Rahman