Data Usage Manager, published by FlavrApps, is a tools app for Android.
Features of Data Usage Manager
It does one job and stays out of the way the rest of the time.
Build details
This build is version 4.7.1 Build 1765, the download runs to about 11MB, and it needs Android 6.0 and up.
The change in this release is listed as Premium Unlocked. Check the file against the scan result on this page before you install it.
Installing
Allow installs from unknown sources for whichever browser or file manager you used, open the downloaded file, and confirm the prompt. If an older copy is present and its signature differs, uninstall that first.