ArchivesSpace actually has a very hands-off approach to data. ArchivesSpace is a tool used to describe the intellectual assets of an archive. Archival description tends to take a somewhat high-level view of the materials in an archive, usually at the shelf, box, and folder level. For particularly noteworthy material, archivists may describe a particular page or group of pages in a folder, and provide access to a digital surrogate of that material.
ArchivesSpace has levels of description at all of these levels. Bundled together, these descriptions are typically called "finding aids" (e.g. an aid for finding the material that is in the archives from a particular donor). For example, this is a finding aid on the demo site for "Jedediah Horcrux Congreave fly fishing correspondence and photographs":
http://demo.archivesspace.org:8081/repositories/2/resources/1
If you scroll to the components of the finding aid and click on "Correspondence":
http://demo.archivesspace.org:8081/repositories/2/archival_ob