Because these are modified versions of copyrighted software, you won't find them on official Microsoft sites. They are typically hosted on:
Some "Light" builds remove the Microsoft Store, Xbox services, or printing support to save space. If you need these, you'll have to reinstall them manually. Download Windows Ultralight (22621 590) FBConan zip
The installed size is often a fraction of the standard 20GB+ Windows installation. Because these are modified versions of copyrighted software,
Often, Windows Defender and Windows Update are stripped or disabled. You are responsible for your own security. Download Windows Ultralight (22621 590) FBConan zip
The primary forums for custom Windows builders.