You must already know that Android is an open system, which allows its users a high degree of customization options in devices that run it. Aside from custom ROMs, the Developer Options menu, and participating in Android beta program, there is also a hidden menu in Android that will let you use new and experimental features to give your device a different look and feel.
It is called System UI, and you will probably never find it unaided because its access is thoroughly embedded somewhere in your device.
The thing is, this feature has been introduced on Android Marshmallow, and it has been updated after the Android 7.0 Nougat rolled out. Reports revealed that the first experimental features introduced in the Marshmallow build has since been implemented in the Nougat version. It is, therefore, expected that the current slew of experimental options could also head to Android 8.0.
How To Use It?
To access System UI Tuner, pull down your Notification panel. You will find the Settings shortcut in the form of a gear icon. This can be found at the top portion of your Quick Settings. Its location will probably vary in some Android skins, but it should be around this area.
Once you spotted it, hold it down for several seconds. Release it after the gear begins spinning.
Once you raised your finger, you will be greeted with a notification window that congratulates you for adding the System UI Tuner to your Settings menu.
To quickly confirm if you have been successful, check if the gear icon has a small wrench symbol beside it.
Now, navigate to the Settings menu, and the System UI Tuner should pop up in the System section, lumped with the Date & Time and Accessibility options.
What Can It Do?
Surprisingly, there are several nifty options available that will let you change or add new elements to the Android interface. As a matter of fact, the menu will be like having a custom ROM.
For example, you can now add seconds in addition to the minutes and hours of your clock. The granular level of the cosmetic changes can also be demonstrated in the tweaks you can make to the Status Bar such as how the charging percentage can be overlaid on the battery icon.
An experimental feature will also let you hide unwanted elements in your Notification panel, while the Others section will also let you deactivate notification alerts from apps.
One should note that there is a persistent warning in the System UI Tuner panel that states how the experimental features could brick your device. It is hidden from view for a reason. Google does not want users to mess with their handsets especially if they don't have any idea about its risks.
If the System UI Tuner has slowed your handset, you can remove it by tapping its three-dot options menu. Just choose "Remove this menu," and reboot your device.