Visible gives you the ability to customize the information you see in the Variables Window. You will notice the listing of Name, Prompt and Value along the top of the window. These are set by default for ease of viewing the variables, groups and expressions. Name and Value will always be present.
If you switch off the Groups option then only the variable names will be displayed, without the group headers.
Variables
Other options offered here are for a Formula column for expressions and a Legend panel so as to help explain the symbols used.
The example below shows the variables without Groups, but including the Formula column.
Variables