Extra files file format 2.0

extra_files.json files provide details about extra (non-RPM, non-image) files included in composes, such as license files, GPG keys, and EULAs.

Changes from 1.x

• size and checksums fields replaced by a location object

• file field now contains only the filename (basename), not the full relative path

• Location objects include url, size, checksum, and local_path fields

• URLs may be HTTPS URLs, OCI registry references, or relative paths

• Checksums use algorithm:hexdigest format (e.g., sha256:abc123...)

• force_version parameter added to serialize() for version control

Location Object

Each extra file entry contains a location object instead of separate size and checksums fields. The location.local_path preserves the v1.x full relative path, while the file field is simplified to just the basename.

See Location for details.

File Format

Compose extra files metadata is stored as a JSON serialized dictionary. It’s recommended to sort keys alphabetically and use 4 spaces for indentation in order to read and diff extra_files.json files easily.

{
    "header": {
        "type": "productmd.extra_files",            # metadata type; "productmd.extra_files" required
        "version": "2.0"                            # metadata version; format: $major<int>.$minor<int>
    },
    "payload": {
        "compose": {                                # see composeinfo for details
            "date": <str>,
            "id": <str>,
            "respin": <int>,
            "type": <str>
        },
        "extra_files": {
            variant_uid<str>: {                     # compose variant UID
                arch<str>: [                        # compose variant arch
                    {
                        "file": <str>,              # filename (basename only) [changed in 2.0]
                        "location": {               # Location object [new in 2.0]
                            "url": <str>,           # HTTPS URL, OCI reference, or relative path
                            "size": <int>,          # file size in bytes
                            "checksum": <str>,      # "algorithm:hexdigest" format
                            "local_path": <str>     # full relative path for v1.x filesystem layout
                        }
                    }
                ]
            }
        }
    }
}

Examples

Fedora 41 extra files:

{
    "header": {
        "type": "productmd.extra_files",
        "version": "2.0"
    },
    "payload": {
        "compose": {
            "date": "20260204",
            "id": "Fedora-41-20260204.0",
            "respin": 0,
            "type": "production"
        },
        "extra_files": {
            "Server": {
                "x86_64": [
                    {
                        "file": "GPL",
                        "location": {
                            "url": "https://cdn.fedoraproject.org/.../Server/x86_64/os/GPL",
                            "size": 18092,
                            "checksum": "sha256:1f2a3b4c...",
                            "local_path": "Server/x86_64/os/GPL"
                        }
                    },
                    {
                        "file": "RPM-GPG-KEY-fedora-41-primary",
                        "location": {
                            "url": "https://cdn.fedoraproject.org/.../Server/x86_64/os/RPM-GPG-KEY-fedora-41-primary",
                            "size": 1714,
                            "checksum": "sha256:2a3b4c5d...",
                            "local_path": "Server/x86_64/os/RPM-GPG-KEY-fedora-41-primary"
                        }
                    }
                ]
            }
        }
    }
}