Kudu is a free, open-source system cleaner + maintenance suite for Windows, macOS, and Linux (MIT license, by Advent Development Inc). The usual catch with free cleaners — closed source, ads, “Pro” paywalls — doesn’t apply. The full code is public, so you can read exactly what every scan and delete does before running it. 
It’s an Electron app (desktop tool built with web tech, same on all 3 OSes):
Windows → NSIS .exeinstaller
macOS → .dmg(Intel + Apple Silicon)
Linux → .deb+ AppImage (one portable file, no install)
Servers → headless Linux Agent (runs as a systemd daemon)
Plus a CLI mode and a portable build on PortableApps.com
Install on Windows (10 build 1809+ / 11) via winget (built-in Windows installer):
winget install --id AdventDevelopmentInc.Kudu --exact
Silent / scripted (push to many machines, no clicking):
winget install --id AdventDevelopmentInc.Kudu --exact --silent --accept-package-agreements --accept-source-agreements
Direct NSIS silent install (skip winget):
Kudu-Setup-X.Y.Z.exe /S
Uninstall:
winget uninstall --id AdventDevelopmentInc.Kudu --exact --silent
The good part: every junk target it can wipe — app caches, browser files, temp folders — lives as plain JSON (readable text) in the public cleaner-rules directory. Read it to see what gets touched, or edit it to add your own. That’s the bit closed cleaners hide.
Source + releases + full rules directory → github.com/AdventDevInc/kudu
Project site → usekudu.com
!