Documentation is now handled by the same processes we use for code: Add something to the Documentation/ directory in the coreboot repo, and it will be rendered to https://doc.coreboot.org/. Contributions welcome!
Coreboot itself can build many other software and include it in the final image. At the time of writing we can, so far:
This is sufficient for most uses cases and can easily be extended to cover new ones. However some external build system still exist, to address uses cases that might not be desirable to cover within the Coreboot build system.