alt-num and ctrl-num?

Can anyone explain to me what the alt-num and ctrl-num variable keystrokes do in the default follow slot X and assist slot X? I can't find anywhere in the settings where those keys are bound to anything.

[bob]

If the Variable Keystroke is not used in the config, then they do nothing.

The setup is so you can use "Assist Slot {SLOT}" as the variable keystroke to be executed, and then ISBoxer will replace the {SLOT} variable with the current active slot. This allows it to be "smart" and send an appropriate key combination to the other windows, so the will assist the calling slot.

If you play WoW, this isn't used, and those settings are not applicable. If you play another game without fancy macros, then it may be applicable, although it is not setup by default to be used.