As I wrote, the app is a mod for Xposed Framework. If you don't know what this is, please check THIS post first.
This mod can set various applications really preciesly. It offers a bunch of settings and features which can the app do:
- DPI: Changes the DPI used by this app both when loading resources (some might be DPI-specific) and also when rendering them.
- Font Scale: Scales the font up or down, similarly to the system-wide "Font Size" setting.
- Screen dimensions: Affects the resources loaded by the app in case it bundles different ones for different screen sizes; use the "List Res." button to get some hints on the kind of alternatives the app might have for different resolutions.
- xlarge qualifier for resources: also affects alternate resources used by the apps (tipically for tablets / devices with big screens); see previous item.
- Locale: the language used by the app for loading resources, formatting numbers and dates, etc.; you can use this for apps that do include translations but don't give you an option of using a different language than your global one.
- Fullscreen: you can force an app to always use fullscreen (hiding the statusbar only, not the navigation bar for devices that have it) or never use it.
- No title: hides the title bar, gaining more space for the actual contents. Note that many apps might crash if they're relying on some elements of the titlebar to be there.
- Keep screen on: If set, the screen won't dim or turn off after the inactivity period whenever this app is on the foreground. Remember not to put the device on your pocket with the app active.
- Show when locked: Display this app's screen on top of the lockscreen, without requiring e.g. the PIN to be entered (dangerous). Note that you'll have to find a way (somewhere else) to open the app from the lockscreen, depending on the kind of app.
- Resident in memory: If set, the system will try much harder to keep the app in memory even when you leave it. It might make the app more responsive when reopening but will also consume more RAM, possibly slowing down the overall system.
- Orientation: Override the orientation settings build into the app. You can force "normal behavior" (rotate according to the device settings, even if the developer hardcoded a specific orientation), "always portrait", "always landscape" or "force auto" (use the sensors even if the auto-rotate system setting is off).
- Insistent notiicationfs: If active, the sounds used by any of the app's raised notifications will loop endlessly. Danger of depleting the battery (and annoying crowds) if you're not around when it starts playing the sound.
- No big notifications: Prevent notifications to have an alternate layout for the "expanded" mode; it will always be collapsed and can't even be expanded manually
- Revoke permissions: selectively block permissions requested by the app. Needless to say, depending on the permission and the app, it's very likely that it will start failing; don't expect revoking INTERNET or READ_CONTACTS and having the apps continuing to work every time - most of them will fail unless the developer anticipated this kind of permission denials.
Nice one, right? All you need to do is to download the app, check it in Modules section in Xposed Framework app and reboot your device to take the effect.