Function manifest_document 

pub fn manifest_document(indexed: &[Artifact]) -> Value

The index of every generated artifact: what each one projects, how it is encoded, what contract it satisfies, where it came from, and its size and hash.

The manifest’s own three files are listed with describes_itself: true and no hash: a document that hashed itself would have no fixed point. Their staleness is not unguarded — generate --check compares every artifact including these byte for byte, which is a stronger statement than a hash the file makes about itself.