By what mechanism is a Document Template linked to the Opportunity, Quote or Order objects?

In Salesforce CPQ, a Document Template is linked to the Opportunity, Quote, or Order objects through the "Applicable Item Types" in Template Settings. This setting allows administrators to define which object types (e.g., Opportunities, Quotes, Orders) the template should be associated with. By configuring this setting, the system knows to present or apply the specific document template when a document generation action is initiated for any of these objects. This mechanism ensures that the correct template is used based on the context of the transaction or the sales process stage.