SDL can be used to replace the Windows Shell with the new big picture mode from Steam, this provides a experience similar to what you would find using the Steam Deck.
Features
Launch directly into Steam's new big picture mode when signing into PC account
Change what happens when you close Steam by opening the CLOSED.LOCATION file with a text editor such as Notepad you can set it to open any program or perform a action such as logging out or shutting down. To log out simply enter SHUTDOWN -L and press save.
Return to SDL mode from the desktop without needing to log out and back in
WARNING!
This will modify a registry key, when installing ensure your using a secondary profile (NEVER USE THE ONLY PC PROFILE ALWAYS CREATE A SEPERATE ONE!).