Question about syntax of @Command([MailAddres]) in R7 template

In the InviteeHotspot (and the others below it) on _Calendar Entry form, there’s the following formula …

@Command([MailAddress];“EnterSendTo”;“EnterCopyTo”;“EnterBlindCopyTo”);

The extra parameters are not documented anywhere … Designer Help only talks about @Command([MailAddress]).

Can anyone help me understand what these parameters are for. Thanks.