Loongson is a major CPU developer from China, which has for years used the MIPS instruction set architecture (ISA)
I'm not sure that's very accurate. From what I've read, the ISA might have some similarities with MIPS, but I think the main thing it borrows is the system-level architecture.
There was some heated debate, in the Linux community, about whether Loongson should be treated as its own architecture or a variation of MIPS. In the course of those exchanges, I think there was a fair amount of people talking across each other, with one one side saying "the ISA is not
like MIPS", and yet much of the kernel support was copy-pasted, because the system architecture was indeed heavily derivative.