Not an official FNAF site
Quoted from the Roblox description.
The games description says this is an unofficial fan game and is not affiliated with or endorsed by Scott Cawthon. It also says original FNAF World characters, music, and assets belong to Scott Cawthon and their respective owners, and that the experience will be taken down if requested by the rights holders. This website repeats that limit. It is not a Scott Cawthon site.