This tool can be found at https://windowsproductkeyextractor.andreaslonn.se
Compatible with (possibly) all versions of Windows. Tested on Windows 10 and 11.
This website uses code from GitHub user mrpeardotnet and can be found at https://github.com/mrpeardotnet/WinProdKeyFinder/blob/master/WinProdKeyFind/KeyDecoder.cs