An autofix file contains a list of words that are automatically replaced by other words during spell-checking. The autofix file is language dependent. For the US English language the file US_AUTOFIX.4SPELL is used (filename syntax is: "language"_AUTOFIX.4SPELL). This file could look like this:
adn=and yuo=youThe word to the left of the equal sign is automatically replaced with the word to the right of the equal sign. In the line "Hello world, how are yuo" the word "yuo" will automatically be replaced with "you" and colored as the autofix color.