Set Voice Key Command: What Does It Do?

In the Key Commands preferences there is a command “Set Voice.” I set up a temporary key assignment to test what this command does, but I can’t discern what happens when I press that key. Also, I don’t find any reference to this command in the Help or Key Commands reference. Any help understanding this would be appreciated.

This command doesn’t currently do anything. (It probably shouldn’t appear in the Key Commands editor, of course, until it does.)