Template expressions are used to configure some Fusion pipeline stage and messaging services. When the value of a configuration parameter is a template expression. That expression is dynamically evaluated at runtime by the StringTemplate library.
Fusion template expressions are delimited by angle bracket characters '<' and '>'. The expression consists of the name of a variable in the scope of that component. Since these variables are Java objects, if object "foo" of type Foo has a field named "bar", the expression "<foo.bar>" will evaluate to the string representation of the contents of field "bar".