Each time you evaluate a command or code selection, the last evaluation result output to the Listener output pane is captured into an internal variable denoted by the ? symbol.
You can access that value again with the ? symbol.
You can use the ? anywhere you normally use a variable name and MAXScript evaluates the ? as the last Listener result.
A common use is to capture the ? value into one of your own variables for later reuse, such as in the following statement:
x = ?