This is for my own clarification, and anyone else that is confused by the terminology here.
In the mid- or late 1990s, I took a processor design class, and RISC was “Reduced Instruction Set Computer”, a generic term for the direction processors were going at the time - even though they had a reduced set of instructions, and therefore had to process more instructions, they could run faster overall because the simplification meant they processed each individual instruction that much more quickly. (IIRC the class textbook was written by the people who had designed the MIPS processor.)
It was my understanding that the speed limitations in the traditional “complex” (CISC) processors were then overcome, so that processor design philosophy continues as well (in particular, x86 architecture is still CISC).
Now, I’m looking this up on Wikipedia: Okay, RISC-V is a set of instructions for a processor, and there are multiple open-source processors that implement RISC-V.
This announcement is that Debian now will theoretically run on those processors. Cool!