Completion requirements
As this is part of the Open Book Collective's 2023 Toolkit for Small and Scholar-Led OA Publishers, the focus is on archiving books. The concise explanations of archives like CLOCKSS/LOCKSS and file formats like XML/PDF/A are nevertheless a good ressource, particularly in the section "Key issues".
Click on Toolkit for Small & Scholar-Led OA Publishers: 13. Archiving and Preservation to open the resource.