There are two kinds of XML Processors:
Non-validating (well-formed)
Validating
Do we need another?
Some specifications mandate that some XML features are forbidden.
Some implementors will build processors for these specifications. In the strictest sense, they are not XML processors: they process a language that's a subset of XML.
Paul Grosso asked, if this was an issue the TAG wanted to address.
The TAG said "yes."