I've hit a roadblock in my intention to use NVDL, related to the validation of nested fragments, and I'm waiting for a hexpert to give me a response to a dumb question I've asked; it turns out that it may not be possible to do exactly what I want to do, so I may have to resort to something more tricky (decomposing the gazetteer.xml file into separate files just for validation purposes). Very annoying. But in the process, I did find some oddities in the gazetteer generation code (such as unnecessary empty tables in the output) which I've now corrected.