This application is a Xposed Module. It allows you to fine-tune MIUI firmware and its applications. There is a lot of options!
The antivirus report has confirmed that MIUI 8 Tweaks is totally safe for usage. Hartec is the developer of this application that is included in the Tools category. On Google Play, the app was rated 3.3 by its users.
The developer released a new version of this application on Jul 24, 2017 and over 100K users downloaded and installed MIUI 8 Tweaks. Get the .apk setup package of MIUI 8 Tweaks 1.17 free of charge and read users' reviews on Droid Informer. You will need 671 KB to install the app which is developed for Android 4.4 and above.
From the users' point of view, the plus of the app is useful features, though some people mention that the weak point of this application is a battery drain.