Taken from the project website (Accessed 2019-12-03):
This website provides an experimental cross-collection search and discovery environment for IIIF-compliant manuscripts and rare books dated before 1800.
The general approach of this prototype is not only to harvest and index the Manifests’ metadata as present at the source, but also to reconcile, cluster and normalise some of the metadata elements in order to enable powerful search capabilities. This data processing uses the big cluster of authorities which forms the backbone of the Biblissima portal.
This is a prototype application, it will be enhanced, updated and enriched on a regular basis.
At present the site contains metadata, and in many cases browsable images, for some 65,000 manuscripts.