@tlaurion @mkukri And Libreboot is dealing with a lot more revs. It has a completely unified build system design. The same script is used for every tree of coreboot, indeed every *project*. There are 7 shell scripts; this is the result of 6 audits spanning 2023 and 2024 where I removed 80% of the build system logic. See:
https://libreboot.org/docs/maintain/
This contrasts the Heads design. Having audited your build system, I can see that you do repeat a lot of (Makefile-based) logic per board/tree/project.