A further thought occurred to me the other day.
I assume that we have to put the source packages in the hwpack too, for at least the packages with some GPL code. Given that hwpacks also serve as a snapshot of the archive, we can't rely on a pointer to the original archive to serve the purpose.
Knowing which packages to include source for will be tricky, so I would implement this as source for all of them, at least to start with.
Thanks,
James