Validator.nu uses (a patched
fork of) oNVDL.
Yet, so far the NVDL part hasn’t
worked.
I enabled NVDL today. It is mostly untested. There’s a bug
tracker.
The reason why the NVDL part hasn’t worked is that the oNVDL
suite and Jing that oNVDL is based on don’t work properly with
application-provided entity resolvers. Since Validator.nu takes
untrusted input, it would be unacceptable to resolve file:
and jar: URIs using the default resolver. It would even
be scary to resolve http: URIs using the JDK’s naïve
built-in HTTP client. As a result, I have to patch every oNVDL
subsystem to do the right thing with custom resolvers. I hadn’t
gotten around to fixing the NVDL subsystem until now. While I was at
it, I applied the same fix to the NRL
subsystem.
The built-in compond document presets don’t use NVDL. This feature
is for those who use custom schemas.