CPU design requires design expertise in several specialties: electronic digital logic, compilers, and operating systems. To cover the costs of such a team, commercial vendors of processor intellectual property (IP), such as Arm Ltd. and MIPS Technologies, charge royalties for the use of their designs and patents. They also often require non-disclosure agreements before releasing documents that describe their designs' detailed advantages. In many cases, they never describe the reasons for their design choices.
RISC-V was begun with a goal to make a practical ISA that was open-sourced, usable academically, and deployable in any hardware or software design without royalties. Also, justifying rationales for each design decision of the project are explained, at least in broad terms. The RISC-V authors are academics who have substantial experience in computer design, and the RISC-V ISA is a direct development from a series of academic computer-design projects, especially Berkeley RISC. RISC-V was originated in part to aid all such projects.