According to the developers, Rebound 11 does not modify any essential system files but offers plenty of new toys for power users to experiment with. After a “simple” installation process, the tool introduces its own WinUI apps that change several aspects of the Windows 11 experience. The package includes a couple of WordPad-style text editors, a modern file explorer, a redesigned Control Panel for managing system settings, and more.
I’d be careful as Microsoft might push an update the breaks the system with installed.