KJOS is a free and open-source debloated windows. It is based on Windows 11 Pro and Windows 11 IoT LTSC.
Everything is detailed on the KJOS website.
If you want to see the KJOS source code, XMLs are available at the root of the project in the source folder.
The XMLs files have been generated by NTLite Software.
Then, import the KJOS preset you just downloaded to see the changes from the Windows Official ISO.