fetch_large_file verified a cached copy and returned its name, which another run replaces when the release serves a re-upload: the caller then packed bytes it never verified. The returned path is now a hard link under .cache/large/.by-sha1/<sha1>/, kept only if it holds the inode that was hashed. Revisions no name holds are dropped a day later. restore_large_files hashes each copy before moving it into place.