Tells a Strategy or Benchmark or Template to use elements from another strategy or benchmark or template
A list of comma-separated names of strategies or benchmarks of templates
Using is most often used by strategies to incorporate elements from templates, but any strategy type can inherit from any other with Using.
All of the elements defined in the used strategy are copied into the using strategy. If the using strategy defines its own version of any of those elements, its own elements replace the ones from the used strategy.
All this is here just to save you from having to re-type (or copy/paste) strategy elements that you use in multiple strategies in a script. Certain elements, such as Commission and Slippage formulas, are often the same for every strategy.
Some of the example scripts, such as mr_sample.rts, incorporate the template/using concept.