*options.txt* is the file that stores all the options changeable in the in-game options menu and various other information the game needs to store after quitting. It is found in the .minecraft folder.
Mouse Sensitivity is not found in the options.txt file even though it is a setting within the in-game options menu,
Cannot reproduce, it shows up as "mouseSensitivity" and also "mouseWheelSensitivity" on my end. Please attach your options.txt.
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