Here is the URL of the page history:
http://www.mediawiki.org/w/index.php?title=Extension:Contents&curid=9306&action=history

river wrote:

the page was somehow created in the wrong namespace. i moved it here: http://www.mediawiki.org/w/index.php?title=Extension:Contents2

wiki.bugzilla wrote:

... and finally moved back to http://www.mediawiki.org/wiki/Extension:Contents
\o/

The page was originally created before the extension namespace existed (i.e. at
:Extension:Contents, in the main namespace).

Thanks for fixing the problem at MediaWiki.org - hopefully there aren't any
other problem pages like this (although I have a vague recollection of there
being one other... I'll let you know if it crops up!)

However, I'm not sure the wider problem is resolved. I.e. that if a page
existed in the main namespace whose name matches a new namespace prefix plus
colon plus title, then effectively this page is uneditable and the content is
lost. The namespace overrides the original content when viewing, but the
original content overrides the new namespace when saving!

I'm sure there was a bug about something similar when the Cookbook: namespace
was enabled at WikiBooks, but I can't find it via the search function.

Some further points:

1. I am unable to move :Extension:Contents from my watchlist (doing so removes

Extension:Contents - the old page cannot be removed).

2. I've discovered what the other page was (as it was also on my watchlist).

:Extension:Skins exists in the main namespace, and will (presumably) cause the
same problems as above if that page is ever created, so perhaps that could be
pre-emptively fixed in the same way as above.

3. I am similarly unable to remove :Extension:Skins from my watchlist (as per

point 1).

Run namespaceDupes.php on your wiki when you add namespaces.

Gah, people keep changing what these bugs describe. It's kinda annoying.

Duping to bug 10171

• This bug has been marked as a duplicate of bug 10171 ***