mikoto is a tweak that allows you to customise various parts of iOS, along with several App Store apps — like YouTube and Twitter.

Some examples of what mikoto can do:

Disable the screenshot preview that appears after a screenshot is taken on iOS 11

Block YouTube ads and enable background playback with full Control Center information

Change the carrier text on the top left to anything you want

Hide promoted tweets and app recommendations in Twitter

Enable Low Power Mode on any device running iOS 9 and above

… and more!

All features are listed and configurable through the mikoto preference pane in the Settings app.