None. Well, yeah, I think SiFive has HDL sources for quite a lot of their stuff up on GitHub, but it's not like you can just compile them into production silicon at home, heck, you can't even verify that the silicon was actually compiled from that source. (Yes there's research into verifiable silicon, but it's not like everyone has ultra high end electron microscopes and whatnot at home lol)

And of course nothing about RISC-V implies that production implementations will be open source at all.