Sure!
First, it is important to understand Output Variables. Any Action has the ability to provide one or more Output Variables. If you open an Action, you can see the Output Variables in the Action tree.
Paired with Output Variables defined in the Action is the Output Name of the test Step. Output Variable are only populated on Steps when an Output name has been specified.
For the Repeat keyword example, lets use MY_REPEAT as the Output Name. While the function defined by your Repeat step is executing, a context variable name MY_REPEAT_index will be populated with the current ZERO based index of the current iteration
AJ