There is μClinux [1] although it is not clear to me how much alive is the project

I wish I could run DiscoBSD/RetroBSD [2] on an ESP32, I like the idea of running on a MCU something that was originally meant for a PDP/11 (2.11 BSD)

[1] https://en.wikipedia.org/wiki/%CE%9CClinux

[2] https://github.com/chettrick/discobsd

you can run linux on riscv without an MMU. There is mainline support for Kendryte K210 chip, so it should be possible port to this chip provided you have enough PSRAM.

Just to get an idea of its capabilities.

Imagine installing Claude Code in it with full root access. Just by asking a few things, you can have a semi-broken ESP32 doing stuff.