This is a custom build combo of both Five Nights at Freddy's gamemode and Five Nights at Pinkie's gamemode that was made for SuperDean.
This custom build is incompatible with the regular builds and maps and was made with the sole intent to be used on a dedicated server.
This custom build strips away many gameplay elements and features for a more streamlined sandbox experience.
If you are really interested in this custom build, you may find a Workshop collection that also contains a custom build of the Sugar Cube Corner map which features a really big outside and other various changes...
You may start your server with +gamemode fnapgmsbox +map fnap_scc
or gamemode fnapgmsbox
when in the console.