List of beans available like execution (execution.getVariable)

What are the list of beans available like execution (used as execution.getVariable) in the modeller directly to be used under script “javascript”.
Or how or where to find them.

Because beans like execution - I am able to use,
but again beans like processEngine - I am unable to use, getting error as undefined.
ReferenceError: “processEngine” is not defined in at line number 5

Because if i want to use any other bean apart from the one listed here:

For example: i want to get version of the process definition in the workflow which is currently executing