A Multi choice parameter represents a set of Boolean values, called multi choice values, which can be either true or false, also called Checked or Unchecked.

Multi choice parameters are typically used when presenting a number of options that can be grouped together but that can be selected independently of each other.

Since it's the multi choice values (not the parameter) that are set during configuration, these are mostly what participate in rules and expression. However, multi choice parameters (with all their values) can be hidden or shown by sub parameter rules.

Multi choice parameters have no specific settings but have most general parameter settings. Note that a multi choice parameter cannot be marked as mandatory, however each of its multi choice values can be marked as mandatory.