optimistic_locking parmeter in vardefs.php (vardefs location for custom modules)

Hi, thanks for looking!

This support documentation page: https://support.sugarcrm.com/Documentation/Sugar_Developer/Sugar_Developer_Guide_10.0/Data_Framework/Vardefs/index.html ...suggests that the vardefs.php file is in the location: 

./modules/Contacts/vardefs.php

For stock modules, I'm guessing.

But where is the location for the vardefs.php file for modules built with Module Builder? When I search the server I can see an auto-generated file in: 

var/www/html/custom/modules/[CUSTOM_MODULE]/Ext/Vardefs/vardefs.ext.php

But this file looks different to the stock modules vardefs.php file.

Thank you