Does anybody know a program that does this?
The X axis of that graph shows timestamps. The most recent peak should be when you last had it plugged in.
KDE is an international technology team creating user-friendly free and open source software for desktop and portable computing. KDE’s software runs on GNU/Linux, BSD and other operating systems, including Windows.
If you encounter a bug, proceed to https://bugs.kde.org, check whether it has been reported.
If it hasn't, report it yourself.
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Developers do not look for reports on social media, so they will not see it and all it does is clutter up the feed.