Module References
Individual modules may be referenced via the following syntax:
%{module:string}
These references are allowed only by a small number of modules that usually perform database lookups. The module name is the actual name of the module, as described earlier. The string portion is specific to each module and is not documented here. It is, however, usually dynamically expanded to allow for additional flexibility.
Examples:
%{sql:SELECT name FROM mytable WHERE username = %{User-Name}}