From version WorkWithPlus 15 Upgrade #1 onwards, when importing modules that use 'User Extended' transaction with GAM, the synchronization between GAM User and the Extended User will be made by the Event Subscriptions of GAM. So, GAM automatically throws the event to synchronize each time a user is modified within the API of GAM. 

This is done by code, and it is imported when the 'User Extended' transaction is imported. And the creation of the subscription events is done when making 'Impact metadata' within WorkWithPlus Menu > Impact Metadata for Web and Native Mobile.