While I'm thinking about nmbug, and the practicality of using it on a
full set of tags, I should mention that there ought to be substantial
speedups possible by caching and only dumping changes since the last
time the cache was updated. I principle this is something I could work
on myself, but I haven't found the time.  One subtlty is that UUIDs and
lastmod values are local to a machine, so probably should not be
committed.

d