Summary
The kernel sub-package build scripts are in an inconsistent state. Some packages are still built with a legacy packaging tool while others already use real Debian packaging, and the legacy path tolerates things Debian tooling doesn't; malformed package names, non-conforming version strings, and cleanup steps that run regardless of build failure, masking real errors.
A few sub-package scripts are written in a different language than the rest of the directory, breaking convention. Kernel flavor configuration is parsed redundantly in two places from the same config file.
Accel-PPP sub-build triggers a full, uncached rebuild of a large dependency (VPP) on every run even though only a few of its libraries are needed.