I'd expect to see material in <noinclude> and not see material that's in <includeonly>, since the page text is being *displayed* not transcluded as a template.

Can you confirm this is what you see?

Yes, that is correct.

See an example here: http://meta.wikimedia.org/wiki/User:Jsoby?action=edit&editintro=User:Jsoby/Test

That makes more sense now, but is still a bit unintuitive in my opinion; There should be a way to have text there that is only displayed when the editintro-included page is shown by itself, while excluding that text when it is included as editintro. Basically, treat the editintro-ed text as a template.

Note: I changed the behaviour of editintro to do what Jon Harald Søby is suggesting be done in r80434 mostly because some users wanted to put interlanguage links on editintro's in <noinclude> sections without them going on to the actual edit pages. Comment 1 makes it sound like that may not have been a good change? I personally think treating it like a template is much more intuitive than the opposite behaviour.

I would back out the change since it is likely to later get FIXME'd. I imagine people are already relying on the non-intuitive behavior.

(In reply to comment #4)

I would back out the change since it is likely to later get FIXME'd. I imagine
people are already relying on the non-intuitive behavior.

I really don't think they are. The current behaviour isn't very useful. Wikipedia uses a {{#ifeq:{{FULLPAGENAME}}|<actual page name>|doc stuff that'd normally be noinclude|includeonly stuff}} (see [[template:Editintro_documentation]] for example)

https://www.mediawiki.org/wiki/Special:Code/MediaWiki/r80434 in the old numbering scheme = 3b84269eb2612e in the new numbering scheme