I think the GP is talking about the Hazard3 [1] core. This is one of the CPU cores besides the ARM M33 instantiated on the RP2350 µC [2]. See this article from Luke Wren (Wren6991) back when the RP2350 came out [3].

[1] https://github.com/Wren6991/Hazard3

[2] https://www.raspberrypi.com/products/rp2350/

[3] https://www.raspberrypi.com/news/risc-v-on-raspberry-pi-pico...

Luke Wren works at Raspberry Pi and designed the Hazard3 CPU core that is in the RP2350 chip.