DOCBOOK-APPS: DOCTYPE for FO?

[Eric Richardson <eric@milagrosoft.com>]

Hi,
I noticed that the generated FO files don't have a DOCTYPE. Is there an
official one so I can edit with PSGML? I found one at
http://www.renderx.com/Tests/validator/fo2000.dtd.

I thought it was reasonable that XSLT would translate XML from one
validatable form to another. It follows that XSL, being XML, should be
able to be validated.

Hope someone can clarify this for me. Thanks.
Eric :-)