Options.txt

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  folder $$ or in the   folder $$, and can be edited with any basic text editor to change options. Most settings can be changed in-game, but a few can be changed only by editing this file.

Java Edition
Each line represents a single option or piece of data, with the option followed by a colon followed by the value of that option. A list of all available key/button numbers for the controls options is available at key codes.