A great deal has been written about these instruments. Missionaries and travellers described them in the nineteenth century, and twentieth-century ethnography returned to them repeatedly, in some cases with photographs and detailed accounts of restricted material. A researcher wanting description can find it without difficulty, and a general encyclopaedia will supply a summary.
That availability is exactly the problem. Some of this material was obtained in circumstances that later scholarship has questioned, in a colonial and missionary setting where consent was not meaningfully available and where the people described had no way to object that anyone would act on. Amazonian communities have since objected, and the objection has not generally reversed anything, because publication is not reversible.
The working principle this atlas applies is that the restriction, not the publication, is the operative fact. If a community keeps something from most of its own members, the accident of it having been printed in 1904 or in 1975 does not convert it into public reference material, and repeating it here would extend the harm rather than record it.
There is a cost to that position and it should be stated. This entry is thinner than the sources would allow, and a reader who wants the detail can find it elsewhere in a few minutes. The atlas is not preventing anything. It is declining to participate, which is a smaller thing, and still worth doing.