are not, due mainly to the lack of support for XML character entities
(e.g. & => & ). This will make it easier to validate test files using
tools like xmllint, as well as edit and view them using XML tools.
on a host with a buggy resolver that strips all but the bottom 8 bits of
each octet. The resolved address in this case (192.0.2.127) is guaranteed
never to belong to a real host (see RFC3330).
