The Greek Orthodox Patriarchate of Jerusalem is a church body first and a manuscript repository second, and the atlas records it here in the second capacity. Its library in the city holds the manuscripts of the Judean desert monasteries, and in particular those of Mar Saba, the monastery founded in the fifth century and inhabited more or less continuously since, whose books were moved into Jerusalem in the 1970s for security and for conservation.
That move is the ordinary modern pattern for monastic libraries and it has an ordinary cost attached. A book in the monastery that made it is where it has always been, and its context, the shelf, the volumes beside it, the community that used it and wrote in it, is part of what the book means. A book moved into a central library is safer, better catalogued, better conserved and far easier to reach, and it has lost that context permanently. Both statements are true at once, and a custodian choosing between them is choosing which kind of loss to accept.
The patriarchate's holdings have been catalogued and photographed by visiting scholars over more than a century, which is how anything at all is known about them outside the library walls. That dependence matters for the case the atlas is most interested in here, because when a manuscript in this collection cannot be produced, the photographs taken by visitors are the only thing that remains of it.