Actum

This is a test release

The installers aren't signed by a store yet, so your system will warn you once:

Android — allow your browser to “install unknown apps” when asked.
Windows — on the SmartScreen prompt, choose “More info” → “Run anyway”.
macOS — after dragging Actum to Applications, run xattr -dr com.apple.quarantine /Applications/Actum.app once, then open it.
Linux — sudo apt install ./actum.deb