If I remember correctly, this tiny binary is used to (reproducibly) bootstrap the next binary, which bootstraps the next binary, until eventually GCC can be compiled (and compile other software).

The bootstrap chain is https://github.com/oriansj/stage0-posix-x86/blob/e86bf7d304b...

To be fair, it is 357 bytes ... plus a POSIX operating system.

Still, that POSIX operating system bit is also being worked on.

Isn't that what builder-hex0 does?

https://github.com/ironmeld/builder-hex0