Those Stupid Days at Famfuck Diner (formely Dayshift at Fredbear's) was a fan game project for DSaF created by Phycic Fredbear. It was going to be a short and simple Adobe Shockwave Player game, redeemed by having some original voice acting.
The short game originally was called Dayshift at Fredbear's and had one page on Game Jolt. When the title was changed, another page was made. The game had only one demo that was released on 01/13/2017 and is still on Game Jolt. The next day, Phycic Fredbear made a devlog asking if anyone has found any bugs, and later, on 02/02/2017, he wrote another devlog promising an update 2 as he was not satisfied with the first demo, even considering it was only a early demo with only one bad ending.
Since then, Phycic Fredbear made no new devlogs. He only came back around June of 2017 to hide the first aforementioned page for the game. It's unknow if the game was either cancelled or just postponed.
Keep in mind: this was never meant to be a full, well-drawned and complex game like the original DSaF games are, but rather a F-bomb joke.