By default, when a FinalBuilder variable's value is referenced in a text field, FinalBuilder will expand the value of that variable recursively. So if the value of myvariable is %anothervariable% then the value of anothervariable will also be expanded. This will continue until no more variable references are found.
In most cases, the default expansion is exactly what we need. In other cases you might require that the recursive variable expansion didn't happen. When referencing the variable in a text field, use a ! symbol in front of the name, e.g %!myvariable% - what this does is tell FinalBuilder to only expand the variable reference, but leave any variable references in the value of that variable unexpanded.