I've been looking at some open-source XMPP servers, and am familiar with the official page http://xmpp.org/. But thus far I've not found anything in between "The Extensible Messaging and Presence Protocol (XMPP) is an open technology for real-time communication" and a list of XEP specifications. For instance articles explaining the basics and terminology - stanzas, IQ, presence, etc, etc. Even the Wikipedia page misses this, unsurprisingly the open-source projects assume you know these things before you start digging into the code.
Is there a good, (semi-)official set of tutorials on this? Do I need to be looking for Jabber resources rather than XMPP?
Amongst other things, I'd hope to see diagrams for use-cases and flow, not just dry protocol text. I know books on XMPP exist, but generally anything in a book is available in some form online too.
Answer
This is probably way too basic, but at least it's technical: https://web.archive.org/web/20170916193014/http://www.adarshr.com/fun-with-xmpp-and-google-talk and the second part, https://web.archive.org/web/20171005104211/http://www.adarshr.com:80/fun-with-xmpp-and-google-talk-part-2
It explains what stanzas are, what types are available and stuff.