Those are the DLC’s in release order, you select one and check the Enable DLC box and it will load that release with all previous updates to the game into Codewalker.
it is like this because as GTAO updates they alter and replace files as well as adding, so this is just a way to make sure your editing the right files for the build you are using 
i cant know for sure which you need but i think in most cases atm it’s “mphiest4”, unless you’ve updated to the latest build and forced the tuner DLC 