Thanks for finding the file and finding instances of the content_actions array.
That helps some. Point of confusion #1 for me appears to have been whether the referenced file was in the distribution I downloaded, or on the CVS/viewvc directory you cited. I had looked there as well, but it has moved from extensions/... to extensions/examples... , thus my confusion.
I'm not up to altering things over there just yet, but for someone who makes it easy, that path might best be revised in the hooks.txt file where I found the reference.
Don't know the answer to Point of confusion #2, but #1 is fixed now in r17138 http://svn.wikimedia.org/viewvc/mediawiki/trunk/phase3/docs/hooks.txt?r1=171... ).
Also the CVS mailing list seems to have stalled at r17109 http://mail.wikipedia.org/pipermail/mediawiki-cvs/2006-October/date.html#end ) ; we're up to at least r17138 now. Can someone maybe give it a kick?
All the best, Nick.