"Unblocked" games are usually versions hosted on Google Sites or dedicated proxy gaming sites (like Unblocked Games 76, 911, etc.). These allow players to bypass network filters. However, be warned: complex 3D horror games like Those Nights at Fredbear's are rarely available to play directly in a browser due to high RAM and GPU requirements. Most "unblocked" versions are actually links to download a lightweight executable file.
: A legitimate repack will contain game data folders and an .exe file. If the download forces you to install an unrelated manager or contains .iso files for a tiny indie game, delete it immediately.