An archiefbeschrijving is an archival description.
To describe their holdings, archives create archival descriptions. Descriptions can be high-over (“incoming correspondence 1800-1810”) or detailed (“accounts of the orphans of Laureijs Smulders, 1606”). Archival descriptions are typically organized per record group and published in the form of finding aids or catalogs.
Most archives in the country have published their archival descriptions online. In a growing number of cases, scans are attached to the descriptions, so you can browse the contents of the records via the finding aid. The description may give access to other services, such as reserving the record for consultation in the reading room or ordering scans. Some archives provide free scanning on demand, usually via a button near the description.