Useful if you need to rename a large number of files in a directory accordingly to their ID3 description and a given "formula" (e.g. (%Track) %Artist - %Title). Such a function is pretty "smart", as it lets you assembly the filename as you wish and use the variables from the ID3 tag in the filename. It is required you mark them with a "%" at the beginning, followed by an ID3 section label (literally - i.e. the first letter is capital, exactly as it is referred to in the roll-down menu).