Final answer:
In the Joint Capabilities Integration and Development System, the document that interfaces is the Capability Development Document (CDD), which details the capabilities and performance criteria for developing a material solution.
Step-by-step explanation:
The Joint Capabilities Integration and Development System (JCIDS) document that interfaces is the Capability Development Document (CDD). This document builds upon the Initial Capabilities Document (ICD), specifying the capabilities and performance criteria that will guide the development of a material solution. The CDD outlines how a proposed system's design should fulfill the required capabilities, and it plays a critical role in the systems engineering process to ensure that the right capabilities are integrated with mission systems.