Despite the templating system being very powerful and capable of producing any kind of output, there are some places in the code where the assumption is made that the system is generating xhtml (such as eg. the debug output layer).

It is more and more important to be able to produce full, rich "web 2.0" interfaces, and being able to do it in eZ without having to resort to custom extensions but simply taking advantage of the templating engine and caching+override mechanisms is a very good thing (TM)

This bug is meant to be a placeholder for all issues related to generation of non-html output.