What is the Battery Widget Reborn (Free) application, how does it work?

According to the introduction of Tomas Hubalek, Battery Widget Reborn (Free) is a Tools app on the Android platform. There is currently a 3.1.21/FREE version released on Jan 27, 2020, you can see the details below.

Application features
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This app provides following functionality:

Battery widget
- circle battery level indicator indicator perfectly fits pure Android design
- resizable on Android 4.x+
- support for both main and external dock battery (Asus Transformer only)

Basic battery info
- Battery Info
- Shortcuts to Power-Summary/Background Sync/Wifi/BT Settings

Status bar notification of battery status
- multiple icon styles
- prediction (estimation) how long battery lasts
- customisable texts in notification area (estimated time left, voltage, temperature, battery health)

Power saving functionality
- automatic power saving mode during the night (simple but powerful battery saver functionality)

Charging and discharging chart

Extended notifications support for Jelly Bean phones
- optional charging and discharging chart
- power related toggles:
- Wifi
- Bluetooth
- Background Sync
- Airplane mode
- customizable notification priority

Additional tools
- Torch
- Settings shortcuts
- DashClock Extension

Specific HW vendor support
- supports Motorola 1% increment
- supports Asus Transformer secondary (dock) battery

Material themed interface on phones with Android 4.0+

Installation and operation notes
=======================
- Task Killer or Task Manager may affect this app. Please don’t use them if app does not work as expected
- App is highly optimized and DOES NOT drain you battery
- Known issues are at http://www.batterywidgetreborn.com/known-bugs.html you can prioritize bug fixes and enhancements there by voting
- Frequently asked questions are at http://www.batterywidgetreborn.com/faq.html, look there before sending support request
- Due to the limitation of the Android platform, home screen widgets will NOT be available if application is moved to SD card.
- Some devices indicate battery level every 10% due to their kernel design (known ones are: most Motorola devices including Droid and Atrix series, Samsung Moment series). Try to use Motorola 1% hack feature if your phone is among these devices
- In Android 4.0, the system may shrink and dim level indicator icons in status bar.

Voluntere for translations at http://translations.hubalek.net/app/bwr

Which version to download?
====================
If you like Material Design install either Free or Pro version
- Free version is Ad supported
- Pro flavor is Ads free.

Install Classic version if you like Holo Theme
- Classic has two options how to reward developer for his effort: either single payment for Pro functionality or Ad Supported version

App made fully compatible with Android 11. Please report any issue you encounter.
Little UI and code polishing
Minor bugfixes
Updated translations