The 'Variable' tag is used to define a variable with a default value. It is not mandatory to use this tag to define a variable before using it,
in fact if the variable was not defined with a 'Variable' tag, then its value will be the PERL default for variable as long as a different
value was not put in it.
Use the 'Variable' tag to have variables with an initial value that you fully want to control.
This tags require two keyword that are both mandatory:
