I am noticing that a request for a NonRdfSourceDescription returns the same ETag value as the NonRdfSource. This isn't an issue for caching proxies, as the resources correspond to different URLs. I also notice, however, that when the NonRdfSourceDescription changes (e.g. via sparql-update), the ETag header for the NonRdfSource also changes. Is that the intended behavior? The bits on the NonRdfSource surely have not changed, so why the new ETag value? This is certainly better than the current behavior -- where a sparql-update on the description changes the ETag on the Binary, but not the description.

That is the correct behavior. The description and the bitstream have an independent existence in HTTP-land, although we had rather they did not. (You will recall that after much thought and argument, it wasn't clear how to merge them.) But they do not have an independent existence as resources in the repository. They each live exactly as long as the other. The properties in question are properties of the resource persisted as the bitstream, not some nebulous and ill-defined "metadata node".