unixnu release runs deps, preflight, patches, build, pack and verify and writes
package.manifest.json (sizes and SHA-256 of boot.img, payload.img and
kernel.macho, module revisions, patch order, command line length). verify
refuses a missing or changed output, a command line of 1000 bytes or more and a
boot image above [package] boot_partition_bytes.
board.toml [package.defconfig] maps an OS profile to its defconfig, and
[os_overrides."<profile>"] merges the values that differ for one profile over
the board; its remove list drops keys the profile does not have. --os picks the
profile, so one branch serves 17, 26 and 27.
templates/package.sh is the device repositories' fixed script. It reads only
[package] unixnu and runs unixnu release.