Web apps can now disable mouse acceleration when capturing pointer events.
Accelerated movement is an ergonomic feature when using a mouse or trackpad to move the pointer on screen. It allows precise movement by moving slowly while also allowing the pointer to cross the entire screen with a quick short motion. Specifically, for the same physical distance that you move the mouse, the pointer on screen travels further if the distance was traveled faster.
Operating systems enable mouse acceleration by default. For some first-party perspective games, commonly first-person shooters (FPS), raw mouse input data is used to control camera rotation without an acceleration adjustment. The same physical motion, slow or fast, results in the same rotation. This results in a better gaming experience and higher accuracy according to professional gamers.