Note that RISC5 [1], a project created as a target for Wirth's Oberon compilers, is a different project from RISC-V [2], a project created at Berkeley which became what is currently the most popular open source ISA.

[1] https://riskfive.com/RISC5_overview.htm

[2] https://riscv.org/

It is funny that RISC-V International moved to Switzerland in 2020 so now both projects can be found in the same place.