Customizing OOTB Actions and Action Models
The incremental attribute is used to indicate that the action or action model is a customization of an OOTB action or action model. Definitions with the incremental attribute will be merged with the corresponding OOTB definitions. This attribute is available for use with the following:
• The objecttype tag of an action definition.
• The action tag of an action definition.
• The model tag of an action model definition.
When customizing an OOTB action or action model, you must include the incremental attribute.