It's a temporary replacement for the current "greetall"-alias, it uses the same menu. Either
- replace the old alias in your file with this one
- create a new file with the new alias, copy the old menu into it, then unload the old file
- add the new alias to the existing file and put the old alias in /* [...] */ quotes (or rename the old alias)

As this one's for testing only, you also could test it without menu by e.g.: /greetall Hello