Consider reading the About page [1]. In summary: RISC‑V is a free and open ISA. They aren't claiming groundbreaking hardware performance and/or design. They are claiming groundbreaking lack of legal/NDA entanglement.
Special bonus/origin story: completely open for academic research and tinkering.
Special bonus/origin story: completely open for academic research and tinkering.
[1] https://www.sifive.com/why