I'm a GNU Emacs user who uses nxml-mode for editing XML files, but I have a colleague who would like to use XEmacs for editing XML files. It seems as though my colleague can't use nxml-mode because the README file for that package says:

To use this, you need GNU Emacs version 21.x, preferably 21.3. GNU Emacs version 20 will not work properly, nor will XEmacs

What is a reasonable way to configure an XEmacs XML mode? Does it ship with one, or are there nice add-ons?

+2  A: 

If I'm not mistaken, XEmacs comes with sgml-mode and psgml-mode.
For more modes to edit XML, see


I used PSGML mode via XEmacs for several years and it is excellent. No support for RELAX NG, but terrific for anything you can dig up a DTD for.