Impact Manifest is an open specification for a
machine-readable change-safety assertion over an infrastructure plan.
terraform show -json says what a change does; an Impact
Manifest says whether it is safe, and, critically, records what could
not be determined, so an unknown can never be silently read as
safe. It is designed to be produced by any tool, for any cloud;
no single implementation owns it.
Published versions are immutable: once a version is here, its bytes
never change, and every version stays up permanently. Manifests carry
an exact version in $id and consumers should pin one;
latest is a browsing convenience only.
provider_id on changes