[layoutIfNeeded]

>Namespace prefixes are absolutely irrelevant, they only exists for your convenience.

This is false. As soon as you need XML canonicalization you very much need those prefices exactly as they were present in the original document.

[lyxsus]

It doesn't affect data model encoded in document even a tiny bit. Namespace prefixes are irrelevant. If changing these prefixes breaks the program, the program is incorrect.

[layoutIfNeeded]

Again, this is false.

“The C14N-20000119 Canonical XML draft described a method for rewriting namespace prefixes such that two documents having logically equivalent namespace declarations would also have identical namespace prefixes. The goal was to eliminate dependence on the particular namespace prefixes in a document when testing for logical equivalence. However, there now exist a number of contexts in which namespace prefixes can impart information value in an XML document. For example, an XPath expression in an attribute value or element content can reference a namespace prefix. Thus, rewriting the namespace prefixes would damage such a document by changing its meaning (and it cannot be logically equivalent if its meaning has changed).”

https://www.w3.org/TR/xml-c14n/#NoNSPrefixRewriting

[lyxsus]

> However, there now exist a number of contexts in which namespace prefixes can impart information value in an XML document.

Well, yeah. They've given up to a mass amount of half-ass implementations? So what? I think it's our moral duty to ignore it :)

[oever]

DTD does not know about namespaces and checks against "prefix:local-name".

E.g. the xhtml dtd will not accept this:

  <h:html xmlns:h="http://www.w3.org/1999/xhtml"/>

If you want to change prefixes, use XML Schema or Relax NG.

[Ygg2]

DTD is the devil spawn. Devil here being massive security vulnerabilities.

[lyxsus]

I would say use XML Schema at least. DTD looks alien to XML anyway.