Thanks to Rhio for the link. Available in French and English. Here's an exerpt from the introduction:
Georges Legrain made an extraordinary discovery in 1903 in the north-west section of the courtyard in front of the Seventh Pylon at Karnak, which had already revealed architectural elements dating from the Middle and New Kingdoms. Over 700 statues in stone, 17000 in bronze and many other artefacts were unearthed during an excavation made difficult due to the infiltrations from the watertable. The work lasted until 1907 and most of the statues ended up in the Cairo Museum. Apart from a certain number of royal effigies from various periods, the statues, which date from the New Kingdom up to the end of the Ptolemaic period, portray priests occupying various functions in Karnak. For this reason, the "cachette" is an extraordinary source of information on the clergy and the ritualistic evolution of Karnak. Genealogies can be reconstituted from the statues of various generations from the same Theban families. The value of this find in terms of the history of art is just as important since a large number of different types of statue are present. Moreover, many small objects of various kinds (stelae, inlay plaques, amulets, votives cubits, etc.) were found by Legrain during these excavations.
Surprisingly for such an important discovery, this corpus of statues and various other objects is still only partially known. Unfortunately, Legrain’s excavation diaries, containing a list of finds (each one bearing a K-number), have never been recovered. Although catalogues of statues have been published by Legrain and more recently by other scholars, there are still many statues, especially in the basement of the Cairo Museum, which are not even mentioned in the Egyptological literature. Furthermore, since the index of the Porter & Moss II, 2nd ed., though still valuable, is now out of date, it is very difficult for Egyptologists to quickly find bibliographical references concerning the objects in this corpus. The recent book on G. Legrain's work at Karnak, published by M. Azim & G. Reveillac, gives an excellent update but only a part of the objects is treated. Furthermore, a comprehensive view of the Cachette is difficult to obtain as some objects found there by Legrain are now on display in provincial museums all around Egypt or kept in foreign museums or collections.
For these reasons, a database project on the Karnak Cachette was launched at the IFAO in 2006.