I'm an XML specialist, doing things like consulting, designing and programming, strictly XML technology only. However, strangely enough, I also like documenting, writing and explaining things to people. Some examples:
I have given various XML, XSLT and other related courses to very different audiences.
Together with Adam Retter I wrote a book about eXist-db, which was published by O'Reilly in 2014.
Some time ago I re-factored the eXist documentation pages (and partly the accompanying application).
I'm currently working on a book about XProc 3.0, to be published when we've finished the standard.
Of course, like probably for everyone, documenting stuff is something I sometimes do as part of the project I'm working on.
In all this, documenting XML structures is unavoidable. So I've tried out different ways and formats and tried to understand why some things work and others don't. This culminated into this (admittedly not very academic but hopefully enlightening) paper.