Enforcing "declare what you mount" refuses the builder, which mounts the
container runtime's socket. That socket is not the builder's data: it
exists already, the machine owns it, and declaring it as one of the
module's directories would be a lie the host would act on.
Two kinds of mount are spelled identically today — the directory my data
lives in, and a machine facility I was granted. Until a manifest can say
which, the fourteen declared mounts are right by coincidence, which is
what this issue was opened about.
Recorded rather than decided: separating them is new vocabulary, and
inventing it to turn a check green is how a mechanism nobody chose ends
up load-bearing.