I’ve always been a fan of extremely small Linux installs. Back when I first started using computers, I didn’t have access to great hardware. In the early 2000s I was using Pentium133 and eventually a Pentium III based system and I remember running floppy Linux (live boot off a floppy disk) and DSL (damn small Linux) in attempts to maximize the performance of the hardware I had.
Running Linux on a tiny ESP32 board just blows my mind!
This article says it works with a risc-v vm of some kind to implement an mmu.
The article OP linked uses this code which doesn’t seem to implement an emulator, though?