Power Saving Mode Checker is an app that helps you check if your phone has built-in doze power saving mode
this app is NOT an app that provide a Power Saving features. Power Saving Mode Checker app just check your own device

What is doze Mode:
Doze reduces battery consumption by deferring background CPU and network activity for apps when the device is unused for long periods of time

Understanding Doze Power Saving Mode:
If a user leaves a device unplugged and stationary for a period of time, with the screen off, the device enters Doze mode. In Doze mode, the system attempts to conserve battery by restricting apps' access to network and CPU-intensive services. It also prevents apps from accessing the network and defers their jobs, syncs, and standard alarms.

Periodically, the system exits Doze for a brief time to let apps complete their deferred activities. During this maintenance window, the system runs all pending syncs, jobs, and alarms, and lets apps access the network.