Switch allows the use of variables in the values of many text properties and for defining file filters. A variable is a special, well-recognizable text string that gets replaced by a dynamic value when the flow is being executed. The dynamic value is recalculated each time in the context of the job being processed.
Variables provide access to run-time information about the flow environment and about a job, including embedded metadata fields (and external metadata fields), without the need for scripting. This lowers the barrier for accessing dynamic information in a flow definition since most users will find it is much easier to use a variable than to create a script expression.