addblock is not used by the spry validation.
it is a validation technique called HoneyPots.
it is a hidden form element that is validated to be empty.
The idea is that a robot hijacking your form will assume that all form elements need to be filled out and submit the form with a value added to the addblock form element causing validation to fail.
It only has to be there if the Server Side validation include the regular expression validation for the addblock field.
//WAFV_Conditional contact.php contact(2:)
Is a comment. it means that the validation show if region is for validatin #2 from the contact.php page.
instead of trying to reverse engineer the code, you could just use the Server Validation functions of the CSS form builder tool.