If you are unfamiliar with this document, do not be vexed. Assumptions are future situations beyond the control of the project,. A functional requirements document (frd)—also known as a functional requirements specification, functional specification, or functional specification document—is a more. Business requirements documents (brds) center on strategic objectives, business processes and user needs at a high level. [provide a list of contractual or task level assumptions and/or constraints that are preconditions to preparation of the frd.