If you’re referring to a or a glitch feature involving squirrels and the number 1636 in FireRed, that’s not part of the official game.
However, for years, people saw a version floating around simply labeled . pokemon fire red squirrels 1636
The numbers "1636" usually refer to the or the internal identifier used by ROM management tools (like GoodTools or No-Intro). If you’re referring to a or a glitch
Why does this matter?