The AIP created by Archivematica includes a README.html file. I translated this file using DeepL (with some manual corrections). There may be many errors, but I hope you find it helpful.

Archivematica AIP Structure

This Readme file describes the basic structure of the Archival Information Package (AIP) generated by Archivematica.

Acronyms

AIP = Archival Information Package

METS = Metadata Encoding and Transmission Standard

OAIS = Open Archival Information System

PDI = Preservation Description Information

PREMIS = Preservation Metadata Implementation Strategies

UUID = Universally Unique Identifier

Introduction

Archivematica is a set of open-source tools designed to ingest diverse digital content and create AIPs for long-term preservation. Once created, an AIP can be opened with a standard file browser without relying on Archivematica. The concept of AIP originates from ISO 14721:2012 Reference Model for an Open Archival Information System (OAIS), defined as “an Information Package consisting of the Content Information and the associated Preservation Description Information (PDI), which is preserved within an OAIS.”

Content Information

In an Archivematica AIP, Content Information primarily consists of the originally ingested digital objects and preservation versions of those objects created to mitigate the risk of format obsolescence over time. Preservation versions typically have the same file name as the original object but with a different file extension and a UUID appended to the file name. For example, for an original file named BBhelmet.ai, the preservation version might be named BBhelmet-e3a3988d-8149-49ea-adc5-c255fb68d4f9.pdf.

The originally ingested digital objects and preservation versions are placed in the AIP’s objects directory. If subdirectories were included in the original transfer or added during SIP arrangement, nested subdirectories will exist within the objects directory. The objects directory also contains a submissionDocumentation folder and a metadata folder. The submissionDocumentation folder contains documents such as donor agreements and transfer forms (if included in the AIP), as well as METS files that record the contents of the original transfer from which the AIP was created. The metadata folder stores metadata files included in the original transfer files and OCR text files generated during processing.

Preservation Description Information (PDI)

The PDI of an Archivematica AIP is recorded in a METS XML file. METS is maintained by the Library of Congress and is defined as “a standard for encoding descriptive, administrative, and structural metadata regarding objects within a digital library, expressed using the XML Schema language of the World Wide Web Consortium.” In an Archivematica AIP, the METS file name consists of the name METS followed by a UUID and an XML file extension. For example, a file name like METS.0ad8cdab-dbbf-4863-8a4d-9a675c227216.xml. The METS file typically consists of the following standard METS sections.

mets:metsHdr (METS Header): Basic information about the METS file.

mets:dmdSec (Descriptive Metadata Section): Descriptive metadata about digital objects.

mets:amdSec (Administrative Metadata Section): Technical and provenance information about digital objects.

mets:fileSec (File Section): A list of digital objects and an indication of their role in the AIP (original, preservation, metadata, submission documentation, license, etc.).

mets:structMap (Structural Map): Physical or logical ordering of digital objects. All AIP METS files contain a default physical structMap and can include additional physical or logical structMaps depending on the AIP’s structure.

The technical and provenance information in the METS amdSec is recorded as PREMIS metadata. PREMIS is also a Library of Congress standard, described as “the international standard for metadata to support the preservation of digital objects and ensure their long-term usability.” PREMIS entities are wrapped within the METS file as follows.

mets:amdSec

--mets:techMD (Technical Metadata)

-—premis:object Example: UUID, size, checksum, format, original name, extracted technical metadata

--mets:digiprovMD (Digital Provenance Metadata)

-—premis:event Example: ingestion, message digest calculation, virus scan, format identification, validation, normalization, fixity check

-—premis:agent Each PREMIS event is associated with three Agents: the organization, the digital preservation system (e.g., Archivematica 1.x), and the login user.

--mets:rightsMD (Rights Metadata)

-—premis:rights Rights related to the preservation, reproduction, and use of preserved digital objects (included only if the user added rights metadata before or during ingest).

The fileSec and structMap link digital objects using identifier attributes. For example, if a file entry in the fileSec has the attribute ADMID="amdSec_1", this means that the amdSec with identifier amdSec_1 contains the administrative metadata (i.e., technical and provenance) for that file. The fileSec also uses group identifier attributes to indicate relationships between digital objects. For example, if file A in fileGrp "USE=original" and file B in fileGrp "USE="preservation" both have the group identifier attribute "Group-269b494d-01cb-451b-8d5e-590d57126d3d", then file B is a preservation version generated from file A.

AIP Structure

An Archivematica AIP is packaged into a bag following the IETF Trust’s BagIt File Packaging Format and contains some content not described in the sections above. This tree structure represents a typical Archivematica AIP.

(1) AIP-name-e3a3988d-8149-49ea-adc5-c255fb68d4f9 (2) ├── bag-info.txt (3) ├── bagit.txt (4) ├── manifest-sha512.txt (5) ├── tagmanifest-md5.txt (6) └── data (7) ├── logs (8) ├── objects (9) ├── thumbnails (10) ├── METS.0ad8cdab-dbbf-4863-8a4d-9a675c227216.xml (11) └── README.html

(1) AIP root directory with appended UUID

(2)-(5) Standard packaging files created based on the BagIt specification.

(6) data directory - This is also a standard directory defined by the BagIt specification. The data directory contains the AIP Content Information and PDI.

(7) logs directory: Contains log output from several tools used by Archivematica when generating the AIP.

(8) objects directory: Contains the original digital objects and their normalized versions.

(9) thumbnails directory: Contains thumbnails generated from the original objects for use in the Archivematica user interface.

(10) Archivematica METS file.

(11) This README file.