One of the more notable features that shipped with Windows 10 is a new filesystem compression system based on the Windows Overlay Filesystem architecture, originally developed for transparent handling of disk images.
It's intended for use in applications, in particular the base OS (in a feature
referred to as CompactOS), but sadly this is only exposed to users via a command
line program —
compact.exe — and most users fail to take advantage of it.
Compactor offers this as an alternative: